The Science & Practice of Perfecting Your Sleep | Dr. Matt Walker

In this episode, my guest is Dr. Matt Walker, Ph. D., Professor of Neuroscience and Psychology and the Founder & Director of the Center for Human Sleep Science at the University of California, Berkeley. He is also the author of the international best-selling book Why We Sleep and the host of "The Matt Walker Podcast." We discuss the biology of sleep, including its various stages and what specifically happens to those stages when we don't get enough sleep. We also discuss the effects of sunlight, caffeine, alcohol, naps, hormones, exercise, marijuana, sexual activity, and various supplements on sleep. The episode consists of both basic science information and many science-supported actionable tools. Read the full show notes for this episode at hubermanlab.com. Thank you to our sponsors AG1: https://athleticgreens.com/huberman LMNT: https://drinklmnt.com/hubermanlab Waking Up: https://wakingup.com/huberman Momentous: https://livemomentous.com/huberman Timestamps 00:00:00 Introducing Dr. Matt Walker 00:02:16 Sponsors: AG1, LMNT & Waking Up 00:06:00 What Is Sleep? 00:10:20 REM (Rapid Eye Movement) aka 'Paradoxical Sleep' 00:16:15 Slow Wave Sleep aka 'Deep Sleep' 00:24:00 Compensating For Lost Sleep 00:32:20 Waking in the Middle Of The Night 00:39:48 Uberman (Not Huberman!) Sleep Schedule 00:42:48 Viewing Morning Sunlight 00:49:20 Caffeine 01:07:54 Alcohol 01:14:30 Growth Hormone & Testosterone 01:16:14 Emotions, Mental Health & Longevity 01:20:40 Books vs. Podcasts 01:21:20 Lunchtime Alcohol 01:25:00 Marijuana/CBD 01:36:00 Melatonin 01:54:14 Magnesium 01:58:10 Valerian, Kiwi, Tart Cherry, Apigenin 02:15:00 Tryptophan & Serotonin 02:19:24 Naps & Non-Sleep-Deep-Rest (NSDR) 02:28:23 Is It Possible To Get Too Much Sleep? 02:34:35 Sex, Orgasm, Masturbation, Oxytocin, Relationships 02:47:30 Unconventional Yet Powerful Sleep Tips 02:59:10 Connecting to & Learning More from Dr. Walker 03:04:42 The New Dr. Matt Walker Podcast, Reviews & Support Disclaimer & Disclosures Learn more about your ad choices. Visit megaphone.fm/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Andrew D. Huberman?

  Welcome to the Huberman Lab Podcast where we discuss science and science-based tools for everyday life.

• 0:09Andrew D. Huberman?

  I'm Andrew Huberman and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, I have the pleasure of introducing Dr. Matthew Walker as our guest on the Huberman Lab Podcast. Dr. Walker is a professor of neuroscience and psychology at the University of California, Berkeley. There, his laboratory studies sleep. They study why we sleep, what occurs during sleep, such as dreams and why we dream, learning during sleep, as well as the consequences of getting insufficient or poor quality sleep on waking states. Dr. Walker is also the author of the international bestselling book, Why We Sleep. Our discussion today is an absolutely fascinating one for anyone that's interested in sleep,

• 0:53Andrew D. Huberman?

  learning, or human performance of any kind. Dr. Walker teaches us how to get better at sleeping. He also discusses naps, whether or not we should or should not nap, whether or not we can compensate for lost sleep, and if so, how to best do that. We discuss behavioral protocols and interactions with light, temperature, supplementation, food, exercise, sex, all the variables that can impact this incredible state of mind and body that we call sleep. During my scientific career, I've read many papers about sleep and attended many seminars about sleep. Yet, my discussion with Dr. Walker today revealed to me more about sleep, sleep science, and how to get better at sleeping

• 1:36Andrew D. Huberman?

  than all of those papers and seminars combined. I'm also delighted to share that Dr. Walker has started a podcast. That podcast, entitled The Matt Walker Podcast, releases its first episode this month and is going to teach all about sleep and how to get better at sleeping. So be sure to check out The Matt Walker Podcast on Apple, Spotify, or wherever you listen to podcasts. Before we begin, I'd like to mention that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero-cost to consumer information about science and science-related tools to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast.

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• 4:12Andrew D. Huberman?

  And now my discussion with Dr. Matt Walker. Great to finally meet you in person.

• 4:16Speaker 07

  Wonderful to connect. I mean, it's been too long, but I suspect it would have been a shorter time before we'd met, lest the pandemic.

• 4:25Andrew D. Huberman?

  Yeah.

• 4:26Speaker 07

  Thank you.

• 4:26Andrew D. Huberman?

  No, thank you. Yeah, I'm delighted that we're finally sitting down face to face. I've been tracking your work, both in the internet sphere, and I read your book and loved it, and also from the perspective of science. You actually came to Stanford a couple of years ago and gave a lecture for Brain Mind.

• 4:45Speaker 07

  Oh, yeah, yeah, yeah, yeah.

• 4:46Andrew D. Huberman?

  And there, of course, you talked about sleep and its utility and its challenges and how to, and how to conquer it, so to speak. Let's start off very basic. What is sleep?

• 5:00Speaker 07

  Sleep is probably the single most effective thing you can do to reset your brain and body health. So that's a functional answer in terms of, you know, what is sleep in terms of its benefits? Sleep as a process, though, is an incredibly complex physiological ballet. And if you were to recognize or see what happens to your brain and your body at night during sleep, you would be blown away. And the paradox is that most of us, and I would think this too, you know, if I wasn't a sleep scientist, we go to bed, we lose consciousness for seven to nine hours, and then we sort of wake up in the morning and we generally feel better.

• 5:43Speaker 07

  And in some ways, that denies the physiological and biological beauty of sleep. So upstairs in your brain, when you're going through these different stages of sleep, the, the changes in brainwave activity are far more dramatic than those that we see when we're awake. And we can speak about deep sleep and what happens there. REM sleep is a fascinating time, which is another stage of sleep, often called dream sleep, which is rapid eye movement sleep. That stage of sleep, some parts of your brain are up to 30% more active than when you're awake. So again, it's kind of violating this idea that our mind is dormant and our body is just simply quiescent and resting. So I would happy to just sort of double click on either

• 6:28Speaker 07

  one of those and also what changes in the body as well. But it is an intense evolutionary adaptive benefit and system. That said, though, I would almost push back against an evolved system. When we think about the question of sleep and what sleep is, our assumption has always been that we evolved to sleep. And I've actually questioned that, and I have no way to get in a time capsule and go back and prove this, but what if we started off sleeping and it was from sleep that wakefulness emerged? Why do we assume that it's the

• 7:08Speaker 07

  other way around? And I think there's probably some really good evidence that sleep may have been the proto-state, that it was the basic fundamental living state. And when we became awake, as it were, we always had to return to sleep. In some ways, at that point, sleep was the price that we paid for wakefulness. And that's another way of describing what sleep is. But again, I think it sort of denies that the active state of sleep, it's not a passive state of sleep either. And then finally, you can say what is sleep across different species. And in us, human beings, and in all mammalian species and

• 7:52Speaker 07

  avian species as well, sleep is broadly separated into these two main types. And we've got non-rapid eye movement sleep on the one hand, and then we've got rapid eye movement sleep on the other. And we can speak about how they unfold across the night and their architecture, because it's not just intellectually interesting from the perspective of what sleep is, it's also practically impactful for our daily lives. And I'd love to sort of go down that route, too. But you navigate, you tell me, I can-

• 8:20Andrew D. Huberman?

  Let's definitely go down that route. So you mentioned how active the brain is during certain phases of sleep. When I was coming up in science- REM sleep, rapid eye movement sleep, was referred to as paradoxical sleep.

• 8:33Speaker 07

  Yeah.

• 8:33Andrew D. Huberman?

  Is that still a good way to think about it? Paradoxical because the brain is so active and yet we are essentially paralyzed, correct?

• 8:40Speaker 07

  Yeah, it really is a paradox. And where that came from was simply the brainwave recordings. That if all I'm measuring about you is your brainwave activity, it's very difficult for me, sitting outside of the sleep laboratory room, to figure out, are you awake? Or are you in REM sleep? Because those two patterns of brain activity are so close to one another, you can't discriminate between them. Yet the paradox is that when you are awake, I go in there and you're sort of sitting up, you're clearly conscious and awake. But yet, when you go into REM sleep, you are completely paralyzed. And that's one of the, I think that's part of the paradox.

• 9:24Speaker 07

  But the paradox really just comes down to two dramatically different conscious states. Yet, brain activity is dramatically more similar than different. And the way I can figure out which of the two you are in is by measuring two other signals. The activity from your eyes and the activity from your muscles. So when we're awake, we will occasionally have these blinks and we'll have sort of saccades. But during REM sleep, you have these really bizarre horizontal shuttling eye movements that occur. And that's where the name comes from, rapid eye movement.

• 10:00Andrew D. Huberman?

  Are they always horizontal?

• 10:01Speaker 07

  Mostly, they are horizontal. And that's one of the ways that we can differentiate them from other waking eye movement activity. Because it's not always, it can be sometimes horizontal, but can also have diagonal and also vertical in that plane. But then the muscle activity is the real dead giveaway. Just before you enter REM sleep, your brainstem, which is where the dynamics of non-REM and REM are essentially played out and then expressed upstairs in the cortex and downstairs in the body. When we go into REM sleep and just a few seconds before that happens, the brainstem sends a signal all the way down the spinal cord.

• 10:43Speaker 07

  And it communicates with what are called the alpha motor neurons in the spinal cord, which control the voluntary skeletal muscles. And it's a signal of paralysis. And when you go into dream sleep, you are locked into a physical incarceration of your own body.

• 11:00Andrew D. Huberman?

  Amazing.

• 11:01Speaker 07

  Oh, you know, why, why would Mother Nature do such a thing? And it's in some ways very simple. The brain paralyzes the body so that the mind can dream safely. Because think about how quickly we would have all been popped out of the gene pool. You know, if I think I'm, you know, one of the best skydivers who can just simply fly. And I've had some times those dreams too, you know, and I get up on my apartment window and I leap out.

• 11:29Andrew D. Huberman?

  You're done.

• 11:29Speaker 07

  You're done, you know? So that's one of the sort of, that's part of the paradox of REM sleep. Both its brain activity similarity, despite the behavioral state being so different. And this bizarre lockdown of the, the sort of brain of the body itself. Now, of course, the involuntary muscles thankfully aren't paralyzed. So you keep breathing, your heart keeps beating.

• 11:53Andrew D. Huberman?

  Is this why men have erections during REM sleep and women have vaginal lubrication during sleep?

• 11:59Speaker 07

  That's one of the reasons. Part of the other reason though, that is because of the autonomic activity. So there is a nervous, a part of our nervous system called the autonomic nervous system. And it controls many of the automatic behaviors. And some of those are aspects of our reproductive facilities. During REM sleep, what we later discovered is that you go through these bizarre, what we call autonomic storms, which sounds dramatic, but it actually is when you measure them. That you'll go through periods where your heart rate decelerates and drops and your blood pressure goes down. And then utterly randomly, your heart rate accelerates dramatically.

• 12:41Speaker 07

  And what we call the fight or flight branch of the autonomic nervous system or the sympathetic nervous system. Badly named because it's anything but sympathetic. It's very aggravating. That all of a sudden fires up and then it shuts down again. And it's not in any regular way. And it's when you get those autonomic storms, you get very activated from a physiological perspective that you can have these erections and you have vaginal discharge, etc.

• 13:06Andrew D. Huberman?

  But you're totally paralyzed.

• 13:07Speaker 07

  But you are still paralyzed. There are only. Two voluntary muscle groups that are spurred from the paralysis. Bizarre. One, your extra ocular muscles, because if they were paralyzed, you wouldn't be able to have rapid eye movements. And the other that we later discovered was the inner ear muscle. And we've got no good understanding as to why those two muscle groups are spurred from the paralysis. It may have something to do with cranial nerve, but I don't think it's that. I think it's perhaps something more sensory related. Some people have argued that the reason the eyeballs are spurred from the paralysis

• 13:51Speaker 07

  is because if your eyeballs are left for long periods of time inactive, you may get things such as oxygen sort of issues in the aqueous or vitreous humor. And so the eyeballs have to keep moving in some way.

• 14:05Andrew D. Huberman?

  The drainage systems of the anterior eye are made to require movement.

• 14:08Speaker 07

  Exactly.

• 14:08Andrew D. Huberman?

  People with glaucoma have deficits in drainage through the anterior chamber. But there I'm speculating. I'm also speculating when I ask this.

• 14:18Andrew D. Huberman?

  I would imagine that there are states in waking that also resemble slow wave sleep, or rather that there are states that slow wave sleep also resembles waking states. You beautifully illustrated how REM sleep can mimic some of the more active brain states that we achieve in waking. What sort of waking state that I might have experienced or experienced on a daily basis might look similar to slow wave sleep, non-REM sleep, if any?

• 14:44Speaker 07

  It's a genius way of thinking about it. Turns the tables. I love it. We almost never see anything like the true ultra slow waves of deep non-REM sleep. So we spoke about these two stages, non-REM and REM. Non-REM is further subdivided into four separate stages. Stages one through four, increasing in their depth of sleep. So stages three and four, that's what we typically call deep non-REM sleep, stages one and two.

• 15:12Andrew D. Huberman?

  So maybe take me through the arc of a night, just so that.

• 15:15Speaker 07

  Yeah, yeah.

• 15:15Andrew D. Huberman?

  So I put my head down. Well, for you, what time do you normally go to sleep?

• 15:20Speaker 07

  So I'm usually. Sort of around about a ten thirty P M guy and usually I'll naturally wake up sort of a little bit before seven, sometimes before six forty five or seven. I have an alarm set for um seven oh four um A M.

• 15:35Andrew D. Huberman?

  You heard it here, folks. Matt Walker does use an alarm clock.

• 15:39Speaker 07

  I rarely, rarely, I'm usually.

• 15:40Andrew D. Huberman?

  He doesn't recommend it, but he does use it.

• 15:42Speaker 07

  Yeah, I usually.

• 15:43Andrew D. Huberman?

  You're human after all.

• 15:44Speaker 07

  Oh, I am so human. Um, and and I've had my sleep issues and I'd love to speak about that, too. But um, it's only just, you know, in the event that um, you know, because I like to keep regularity, too. You've got to keep those two things in balance. And seven oh four, just because, you know, why not be idiosyncratic? Uh, I don't know why we always set things on these uh hard numbers. So, yep, so when.

• 16:08Andrew D. Huberman?

  So you'll go to sleep around ten thirty. So using you as an example, um, because I imagine a number of people go to sleep at different times, but ten thirty is about when I go to sleep. Eleven is for me, but um, so you go to sleep at ten thirty. So for that first, um, let's say, three hours of sleep, wh- what is the architecture of that sleep look like as compared to the last three hours of your sleep uh before morning?

• 16:29Speaker 07

  Yeah. So I should note that that sort of, you know, ten thirty to seven, that's just based on my chronotype and my preferential. It's different for different people. I'm not suggesting that that's the perfect sweet spot for humanities sleep. It's just my.

• 16:43Andrew D. Huberman?

  But I imagine most people probably go to sleep somewhere between ten and P M and midnight. And most probably wake up between five A M and seven A M or or five thirty and seven thirty.

• 16:56Speaker 07

  Yeah, yeah. Um, at least in, if you look at sort of First World Nations, that's that's a typical sleep profile. Um, so when I first fall asleep, I'll go into the light stages of non-rem sleep, stages one and two of non-rem. And then I'll start to descend down into the deeper stages of non-rem sleep. So after about maybe twenty minutes, I'm starting to head down into stage three, non-rem, and then into stage four, non-rem sleep. And as I'm starting to fall asleep, as I've cast off from the uh usually with me murky waters of wakefulness, um, and I'm in the shallows of sleep, stages one and two, my heart rate starts to drop a little bit. And

• 17:37Speaker 07

  then my brainwave pattern activity starts to slow down. Normally, when I'm awake, it's going up and down maybe twenty, thirty, forty, fifty times a second. As I'm going into light non-REM sleep, it will slow down to maybe fifteen, twenty, and then really starts to slow down, down to about sort of ten or eight cycles per second, eight cycle waves per second. Then, as I'm starting to move into stages three and four non-REM sleep, several remarkable things happen. All of a sudden, my heart rate really does start to drop.

• 18:15Speaker 07

  Oh, and I'll come back to temperature. I'm going to write temperature down because I always forget these things. Now I'm sadly in the foothills of middle age. So as I'm starting to go into those deeper stages of non-REM sleep, all of a sudden, hundreds of thousands of cells in my cortex all decide to fire together, and then they all go silent together. And it's this remarkable physiological coordination of the likes that we just don't see at during any other brain state.

• 18:46Andrew D. Huberman?

  That's really interesting. Having recorded from the brains of animals and a little bit from humans, I don't think I've ever seen the entire cortex or even entire regions of cortex light up like that.

• 18:55Speaker 07

  Yeah, it's stunning. It's almost like this beautiful sort of mantra chant, or this sort of, you know, it's a slow inhale and then a meditative exhale, inhale, exhale, and these waves are just enormous in their size.

• 19:11Andrew D. Huberman?

  And the body is capable of movement at this time. There is no paralysis.

• 19:15Speaker 07

  There is no paralysis, but for the most part, muscle tone has also dropped significantly at that point. And then you will, or I will then stay there for about another twenty or thirty minutes. So now I'm maybe sixty or seventy minutes into my first sleep cycle. And then I'll start to rise back up, back up into stage two non-REM sleep. And then after about eighty or so minutes, I'll pop up and I'll have a short REM sleep period. And then back down I go again, down into non-REM, up into REM. And you do that reliably repeatedly, and I will be doing that, and I do do that, every ninety minutes. At least, that's the average for most adults. It's different in different species.

• 20:00Speaker 07

  What changes to your question is the ratio of non-REM to REM within that ninety-minute cycle as you move across the night. And what I mean by this is, in the first half of the night, the majority of those ninety-minute cycles are comprised of lots of deep non-REM sleep. That's when I get my stage three and four of deep non-REM sleep. Once I push through to the second half of the night, now that seesaw balance changes, and instead, the majority of those ninety-minute cycles are comprised either of this lighter form of non-REM sleep, stage two non-REM sleep, and much more and increasingly more rapid eye movement sleep.

• 20:40Speaker 07

  And the implication that I was sort of speaking about pragmatically is, let's say that I have to, and I usually never do early morning flights or red eyes, just because I'm a mess if that happens, I'm not suggesting that other people shouldn't.

• 20:55Andrew D. Huberman?

  I'm suggesting people not do that. Every time I've taken a red eye or I've done that, two or three days later, I get some sort of general feeling of malaise, my brain doesn't work as well. I think red eyes should be abolished.

• 21:06Speaker 07

  I

• 21:07Andrew D. Huberman?

  For the pilots, too. I mean, and for the

• 21:09Speaker 07

  And we can speak about those

• 21:10Andrew D. Huberman?

  And for the emergency room, I mean, long shifts have been shown to lead to, you know, physician-induced errors that lead to a lot of fatalities. I mean, there are a lot of reasons why staying up too long or being up at the wrong times, if you're not adapted to, is just terrible.

• 21:24Speaker 07

  The data in all of those cases, you know, and particularly physicians, too, there was some recent data looking at suicidality. And the rates of suicide in training physicians are, you know, far, far above the norm. And I don't suspect that, you know, their schedules are helping them. I suspect that sleep is a missing part of that explanatory equation, but

• 21:47Andrew D. Huberman?

  I teach medical students, and they, they're phenomenal, but they, yeah, they're under extremely challenged conditions.

• 21:53Speaker 07

  We shouldn't put them under

• 21:54Andrew D. Huberman?

  No, it's not, it's not optimizing performance.

• 21:57Speaker 07

  But, sorry, I was, sorry.

• 21:58Andrew D. Huberman?

  No, no, this is important, these, it's an important digression. I have one question, which is, you're saying that as across the night, a greater percentage of these ninety-minute cycles are going to be occupied by REM sleep as you progress through the night?

• 22:14Andrew D. Huberman?

  I'm aware that based on work that you've done and and from your public education efforts and others that we have so-called circadian forces and we have other forces that are driving when we sleep and when we want to sleep, etc. Without going into the details of those, I have a simple question. The experiment is the following. Let's say, God forbid, you are prevented from going to sleep at your normal time and you stay up for the four hours or five hours that normally you would be in predominantly slow wave sleep.

• 22:47Speaker 07

  Yep.

• 22:47Andrew D. Huberman?

  If, let's say you finally get to lie down at 3:00 AM, a time when normally your sleep would be occupied mostly by rapid eye movement sleep.

• 22:57Speaker 07

  Yep.

• 22:58Andrew D. Huberman?

  Will you experience a greater percentage of rapid eye movement sleep because of these so-called circadian forces, meaning that's what's appropriate for that time? Or will your system need to start at the beginning of the race that we're, as I'm referring to it, that we're calling sleep?

• 23:15Speaker 07

  Yep.

• 23:16Andrew D. Huberman?

  If that's not clear to anybody, basically what I'm asking is if you are forced to skip the slow wave sleep part of the night, will your system leap into rapid eye movement sleep? Or does it have to start at the beginning and get slow wave sleep first? In other words, does one sleep state drive the entry to the next sleep state?

• 23:33Speaker 07

  Great question. So there is some degree of reciprocity between the sleep states. I should note that when we drive one of those up, we often, but not always, see a change in the other. There are some pharmacologies that have shown an independence to that. And we've also played around with things like temperature and sometimes you can, you know, nudge one and not seem to upset or perturb the other. But to your, I think, lovely point.

• 24:03Speaker 07

  The answer is it's a mix, but it's mostly the latter. Meaning you will mostly go into your REM sleep phases and be significantly deficient in your deep sleep. So just because I start my sleep cycle at 3am rather than at 10:30pm, it doesn't mean that my brain just says, well, I've got a program and I'm just going to run the program. And the way the program runs is that we always start with the first couple of hours of deep sleep. So we're just gonna begin act number one, scene one. It doesn't do that. Now, I will get some deep sleep to begin with. And part of that is just because of how sleep works, based on how long I've been awake.

• 24:48Speaker 07

  Longer I'm awake, there is a significantly greater pressure for deep sleep. But we actually use exactly what you just described as an experimental technique to selectively deprive people of one of those stages of sleep or the other. So we will do first half of the night deprivation and then let you sleep the second half. So that means that you will be mostly deep sleep deprived and you will still get mostly all of your REM sleep. And then we switch it. So you only get your first four hours, which means you will mostly get deep non-REM sleep, but you will get almost no REM sleep. So in both of those groups, they've both had four hours of sleep.

• 25:29Speaker 07

  So the difference between them in terms of an experimental outcome is not the sleep time, because they've both slept for the same amount. It's the contribution of those different stages. Now, we actually have more elegant methods for sort of selectively going in there and scooping out different stages of sleep. But that's the way we used to do it old school, was just using this timing difference.

• 25:51Andrew D. Huberman?

  And who suffers more? Those that lack the early phase or those that lack the later phase of the night sleep? In other words, if I have to sleep only four hours, for whatever reason, am I better off getting the early part of the night sleep or the second half of the night sleep?

• 26:06Speaker 07

  Depends on what the outcome measure is.

• 26:09Andrew D. Huberman?

  Um. So that gets right to the differences between slow wave sleep and REM.

• 26:13Speaker 07

  Right.

• 26:13Andrew D. Huberman?

  I was um probably misinformed, but my understanding, a very crude understanding, I should, I should say before.

• 26:20Speaker 07

  I very much doubt it. No contra with someone like you.

• 26:22Andrew D. Huberman?

  Yeah, which is that that very nice of you, but the the the first part of the night, the slow wave sleep is restorative to the musculature, to motor learning, and that the dream content tends to be less emotional. The second half of the night being more emotional dreams and sort of the unpairing of the emotional load of our previous day and other experiences. So in other words, if I were to deprive myself, deprive myself, excuse me, of REM, I would be hyperemotional, not maybe not as settled with the kind of experiences of my life. Whereas if I deprive myself of slow wave sleep, I would um feel a more physical malaise. Is that correct? Or is that far too simple? And if it is too simple, please uh tell me where I'm wrong.

• 27:01Speaker 07

  No, I think much of that is correct, and it's sort of that plus. So, for example, during deep non-REM sleep, that's where we get this. It's almost a form of natural blood pressure medication. And so when I take that away from you, the next day, we're usually going to see autonomic dysfunction. We're usually going to see abnormalities in heart rate, blood pressure. We also know that during deep non-REM sleep, that there is a certain control of specific hormones. For example, we know that the insulin regulation of sort of metabolism, um meaning how will you look from a regulated blood sugar perspective versus dysregulated pre-diabetic look of profile?

• 27:43Speaker 07

  That's where deep sleep seems to matter. If we selectively deprive you of that, we can see.

• 27:48Andrew D. Huberman?

  Growth hormone.

• 27:49Speaker 07

  Growth hormone is different, actually. So that's that's a beautiful demonstration where growth hormone seems to be more REM sleep dependent. And that's why we can come on to the effects of alcohol. And there was there's some really impressive frightening data on on alcohol and its disruption of um of sleep. But then we also know testosterone. You know, peak levels of testosterone happen during REM sleep.

• 28:12Andrew D. Huberman?

  It's the second half of the night.

• 28:14Speaker 07

  It which is the second half of the night. So it really just means that the your profile of mental and physical dysfunction will be different under both of those conditions. Which one would you prefer? I would prefer neither of them, and it really depends on what you're trying to optimize for. So it's it's just so complex, you know, sleep is just so pluripotent. You know, it's so physiologically systemic that it's almost impossible not to undergo one of those two things, just deep sleep deprivation or just REM sleep deprivation, and not show a profile that you would really prefer to avoid.

• 28:57Speaker 07

  Uh, and that's the that's the reason from an evolutionary standpoint that we have preserved those stages of sleep. I mean, sleep is just so idiotic, you know, from an evolutionary perspective.

• 29:08Andrew D. Huberman?

  Or maybe waking is idiotic.

• 29:10Speaker 07

  Or waking is, you know, I well, yeah.

• 29:12Andrew D. Huberman?

  Based on your previous idea.

• 29:14Speaker 07

  Who have you been talking to? I think that comment is very specific to me. Um, yeah, I am normally um, always an idiot when waking. But I think this this idea that sleep, you know, is so profoundly detrimental to us. If you were to take it at face value, you know, you're not finding a mate, you're not reproducing, you're not foraging for food, you're not caring for your young, and worst of all, you're vulnerable to predation. On any one of those grounds, sleep probably should have been selected against. But it wasn't. Sleep has fought its way through heroically, you know, every step along the evolutionary path. And therefore, every sleep stage has also survived as best we can tell.

• 29:59Speaker 07

  What that means is that those are nonnegotiable. If Mother Nature had found a way to even just sort of, you know, thin slice some of that sleep from us, there would have been vast, I'm sure, evolutionary benefits. But it looks as though she hasn't, and I'm usually in favor of her wisdom after 3.6 million years, so.

• 30:21Andrew D. Huberman?

  Yeah, it's it's incredible. I want to introduce a another um, Gedanken experiment, another thought experiment. So in this arc of the night, uh, slow wave sleep predominates uh, early in the night and then REM sleep. There's a scenario that many people, including myself, experience on a regular basis, which is they go to sleep, sleeping just fine, three, four hours into it, they wake up.

• 30:44Speaker 07

  Yeah.

• 30:45Andrew D. Huberman?

  They wake up for whatever reason. Maybe it was a noise, maybe the temperature isn't right. We will certainly talk about sleep hygiene, et cetera. They get up, they go to the restroom, they might flip on the lights, they might not. They'll get back in bed. Hopefully, they're not picking up their phone and starting to browse and wake up the brain through various mechanisms, light and cognitive stimulation, et cetera. They go back to sleep. Let's say after about 10, 15 minutes, they're able to fall back asleep and then they sleep till their more typical wake time.

• 31:14Speaker 07

  Yeah.

• 31:15Andrew D. Huberman?

  How detrimental is that wake up episode or, or event in terms of longevity, learning, et cetera? I would love to sleep the entire night through every night, but most nights I don't. And yet I feel pretty good throughout the day, some days better than others.

• 31:34Speaker 07

  Yeah.

• 31:35Andrew D. Huberman?

  So if you were to kind of evaluate that waking episode and compare it to sleeping the whole night through, what are your, what are your thoughts on that?

• 31:46Speaker 07

  So I think if you're waking up sort of frequently as you're describing, I would probably get your estate in order because my guess is within the next year, you're gonna be, you're gonna be done for, no, I'm kidding you, absolutely kidding you. It is perfectly natural and normal, particularly as we progress with age. You know, children tend to have typically more continuous sleep. Now, it's not that they aren't waking up for brief periods of time, they are. And in fact, we all do. When we come out the other end of our sleep cycle, at the end of our REM sleep period of the 90 minute cycle, almost everybody wakes up and we make a postural movement.

• 32:27Speaker 07

  We turn over because we've been paralyzed for so long and the body will also like to shift.

• 32:32Andrew D. Huberman?

  Do we ever look around, do we ever open our eyes position?

• 32:35Speaker 07

  You, sometimes people will open their eyes, but usually it's only for a brief period of time and they usually never commit those awakenings to memory.

• 32:44Andrew D. Huberman?

  Right.

• 32:45Speaker 07

  Your situation, and it's my situation as well, I usually now at this stage of life, I don't sleep through the night. I'll usually have a bathroom break and then I'll come back. That's perfectly normal. We tend to forget that in sleep science, we think of sleep efficiency. So of the total amount of time that you're in bed, how much of that percent time is spent asleep? And we usually look to numbers that are above eighty five percent or more as a healthy sleep efficiency. So if you were to think about me going to bed and I spend, you know, let's say,

• 33:26Speaker 07

  eight and a quarter, eight and a half hours of time in bed with a normal, healthy sleep efficiency. I still may be only sleeping a total of seven and a half hours or seven and three quarter hours. Meaning that I'm going to be awake in total, not in one long bout. But I'm going to be awake for upwards of thirty minutes net some time. Sometimes that can be after a ten minute, you know, dalliance after having gone to the bathroom and I'm just gradually drifting back off again. Other times it will just be for a couple of minutes and most of those you don't commit. So I think we need to stop, we don't need to get too worried about, you know,

• 34:11Speaker 07

  periods of time awake just because we're not sleeping throughout the night. I would love to do that too. And I remember when I, that used to happen and it still happens.

• 34:19Andrew D. Huberman?

  Everyone's like, feels great when it does happen.

• 34:21Speaker 07

  It's a lovely thing.

• 34:22Andrew D. Huberman?

  It's a surprise, right?

• 34:23Speaker 07

  It is not now a surprise.

• 34:25Andrew D. Huberman?

  The whole night.

• 34:25Speaker 07

  Yeah, it is a surprise. But for the most part, I think we can be more relaxed about that. Where we have to be a bit more attentive though, is if you are spending long periods of time not being able to get back to sleep. And usually we define that by saying if it's been twenty, twenty-five minutes. Normally that's a time when we would really say, okay, let's explore this. What's going on? Let's see what's happening. The other thing is if it's happening very frequently. So even if you're, um, you know, not awake for twenty-five minute stretches, but you're finding yourself waking up and being consciously aware that you've woken up for maybe six, seven or eight times throughout the night.

• 35:08Speaker 07

  And your sleep is very, what we call fragmented. The great science of sleep in the past five or 10 years has been, yes, quantity is important, but quality is just as important. And you can't have one without the other in terms of a good beneficial next day outcome. You can't just get four hours of sleep, but brilliant quality of sleep and be unimpaired. Nor can you get eight hours of sleep, but have very poor quality of sleep and be unimpaired the next day. So that's why I just sort of want to asterisk this idea of let's not get too worried about waking up and having some time awake. That's perfectly normal and natural.

• 35:53Speaker 07

  But if it's happening very frequently throughout the night, or those periods of time, or long stretches of time upwards of 25 minutes, then let's look into it.

• 36:02Andrew D. Huberman?

  Well, I can assure you, just helped a lot of people feel better about this waking up episode that I and many other people experience.

• 36:11Speaker 07

  I hope so, because I think it's really important that we, you know, I think I've been desperately guilty of perhaps, you know, early on being too puritanical about, you know, sleep and, and I've, I've retrospected and I've tried to explore why this was the case, you know, it was almost sleep or else, dot, dot, dot. And at the time when I was starting to write the book, which was back in 2016, you know, sleep was still a neglected stepsister in the health conversation of today. And I could see all of the, and it's changing, you know, and not because of my efforts, but because of all of my colleagues.

• 36:51Andrew D. Huberman?

  I would say, well, I, it's a great that you give attribution to your other people involved in, of course, it's a big field, but I think you've done a great service by cueing people to the importance of this state, not just for avoiding troublesome outcomes, but also for optimizing their waking state. It's really, you know, I, I view sleep as this period that feels good, but we're not aware of how it feels when we're in it necessarily.

• 37:17Speaker 07

  Yeah.

• 37:18Andrew D. Huberman?

  It has tremendous benefits when you're doing it well, so to speak, and it has tremendous deficits when, when we're not. And I think. I think it was an important thing for you to do to cue people to this issue. And I would say, mission accomplished. That people are aware of the need for sleep. I think that knowing that waking up in the middle of the night is normal, provided it's not too frequent, is is great and will also help people who may have been overly concerned about that. I I do want to use this as an opportunity to raise something about the so-called Uberman schedule, not to be confused with the Huberman schedule. Fortunately, no one has confused those yet.

• 38:02Andrew D. Huberman?

  Some years ago, there was a discussion about the so-called Uberman schedule, meaning the Superman schedule. So that's Huberman without an H, which I have nothing to do with. If you read your Nietzsche, this will have a subtext. But regardless, the Uberman schedule, as I understand, is one in which the person elects to sleep in 90-minute bouts spread throughout the day and night in an attempt to get more productivity and or reduce their overall sleep need. There was a paper published recently that explored whether or not this is good or bad for us. Maybe you just give us the take-home message on that.

• 38:40Speaker 07

  Yeah, so these Uberman-like schedules, and there's lots of different forms of that. They tried to essentially pie chart the 24-hour period into short bouts of sleep with some shorter or no, well, slightly longer periods of wakefulness, then short bouts of sleep, then wakefulness. You know, you're, I sort of made it, I think, a quip. It's almost like you're sleeping like a baby. You know, because that's the way that babies

• 39:07Andrew D. Huberman?

  In 90-minute naps.

• 39:08Speaker 07

  That they will have, you know, these brief naps, then they're awake, then they're asleep, then they're awake. And to the chagrin of parents, across the night, it's basically the same. They're awake, they're asleep, they're awake, they're asleep. And that's more the the schedule that these types of protocols have have suggested. And there was a really great, comprehensive review that found not only that they weren't necessarily helpful, but they were actually really quite detrimental. And on almost every performance metric, whether it be task performance, whether it be physiological outcome measures, whether it even be the quality of the sleep that they were having when they were trying to get it, all of those were in a downward direction.

• 39:50Speaker 07

  And it's not surprising, if you look at your, the way that your physiology is programmed, if you look at the way your circadian rhythm is programmed, none of that screams to us that we should be sleeping in that way.

• 40:03Andrew D. Huberman?

  Well, I'm chuckling because we always hear, sleep like a baby. This is how babies sleep. And I would say, don't sleep like a baby, sleep like an adult.

• 40:11Speaker 07

  Yeah, I mean.

• 40:11Andrew D. Huberman?

  Get your solid eight hours.

• 40:13Speaker 07

  It's Billy Crystal's line, who's a, you know, a longstanding, suffering insomniac. He says, I sleep like a baby, I'm awake every 20 minutes. You know, and I think this is another one of those demonstrations that when you fight biology, you normally lose. And the way you know you've lost is disease, sickness and impairment. And I think if you sleep in accordance with the natural biological edict that we've all been given, life tends to be both of a higher quality and a longer duration.

• 40:46Andrew D. Huberman?

  Yeah, I agree. Along those lines, I'm, as a vision scientist, I've been very excited by the work on these non-image forming cells in the eye, the so-called melanopsin cells that inform the brain about circadian time of day. And I'm a big proponent of people getting some sunlight, ideally sunlight, but other forms of bright light into their eyes early in the day and when they want to be awake.

• 41:07Speaker 07

  Yep.

• 41:08Andrew D. Huberman?

  Essentially during the phase of their 24 hour circadian cycle when temperature is rising. And then starting to get less light in their eyes as our temperature is going down in terms of later in the day and in the evening. Are there any adjustments to that general theme that you'd like to add? Or is, in any way?

• 41:27Speaker 07

  No, I think that's exactly what we recommend right now, which is try to get at least 30 to 40 minutes of exposure to some kind of natural daylight. Now, there may be parts of the world where, you know.

• 41:40Andrew D. Huberman?

  You're from, you're from a rather cloudy part of the world.

• 41:42Speaker 07

  I am from, yeah, Liverpool, England. And the northwest of England is not known for its beach resorts and fine weather. I remember I sort of, I went back home for a trip when I'd first been out in California. And I thought, why is the sky so low? You know, it's just, you know, constantly, we joke that in, in the UK, we usually have nine months of bad weather and then three months of winter. And then that's your, that's your entire year of, in terms of a climate, but. To come to your point, you're exactly right. Try to get that daylight. Now, it can be, you know, working next to a window and you're getting that natural sunlight. But that natural

• 42:27Speaker 07

  sunlight is even on a cloudy day in England is usually far more potent than anything that you'll get from indoor lighting. Despite you thinking sort of from a perception wise, maybe they're that much closer than I would think.

• 42:42Andrew D. Huberman?

  Yeah, I've been, um, sorry to interrupt. I've been a big proponent of there's a, an app called light meter, which well, it's a free app. I have nothing to do with it. They will allow you to get a pretty decent measurement of the amount of, of light energy coming toward you. And if you, um, hold it up to a cloudy morning where you don't think it's very bright out, kind of a dismal day, you'll notice that there'll be a thousand, two thousand, even, you know, 5,000 lux, lux just being a measure of brightness, of course. And then you can point the same light meter toward an indoor light that seems very bright and very intense, and it'll say 500 lux. And you realize that the intensity as we gauge it perceptually is not really what the system is receiving. So outdoor light is key. How do you, how do you get this natural stimulation? Or, um, I should just say light stimulation

• 43:27Andrew D. Huberman?

  early in the day. What is your typical, what does Matt Walker do to get this light stimulation?

• 43:32Speaker 07

  I am no poster child, but, um, usually I will, um, if I'm working, I usually work out most days. Um, and I shopped around and I found a gym that has huge amounts of window exposure facing to the east. This is sound, this is going to sound so ridiculous, you know, Matt Walker chooses a gym on the basis of the solar input. So he can, you know,

• 43:55Andrew D. Huberman?

  There are a lot of criteria for selecting gyms. This one is actually grounded in physiology and biology. And so

• 44:01Speaker 07

  And selfishness about my own sleep.

• 44:03Andrew D. Huberman?

  That's great. So you, so you get your exercise and your light stimulation simultaneously?

• 44:07Speaker 07

  Yep, yep.

• 44:07Andrew D. Huberman?

  And so you're stacking cues for wakefulness early in the day.

• 44:11Speaker 07

  Exactly. So both exercise and daylight are wonderful cues for circadian rhythm alignment and also circadian rhythm reset each day. And so I will use both exercise. I mean, I am, I'm neither a strong morning type or a strong evening type. My preference to exercise is probably sometime in the middle of the day. Um. Probably somewhere around one A, one P M. Sorry, not one A M. Um. But I'm usually working out probably around the sort of seven sort of forty five, eight. Uh. A M. Time. That's usually when I'll start my workout. And there I'll start with cardio, spin bike, facing a window. And luckily, for the most part here in California, there's usually sunlight coming through.

• 44:57Speaker 07

  But it doesn't matter to me because, just as you said, even when it's a cloudy day, that luck's coming through of light, the, the, the intensity is, is splendid. So I would prefer to favor my exercise, just because for efficiency too, I want to get also working on the day. Um. I'll try to match my exercise more with my circadian light exposure than I would probably if I'm going to, do I really want to crush a workout? Or do I want to just, you know, make sure it's a good workout? I would prefer to work out, you know, at a different time, but I like that because of the daylight. And we can speak about exercise timing at some point because there's a lot of discussion around that.

• 45:40Speaker 07

  When is the right time to exercise during sleep? And we can sort of bust some myths there too. Um. So I think you're spot on with the suggestion. Get some morning daylight, try to get that exposure, usually at least thirty to forty minutes. There was some great work recently coming out in the occupational health domain where they moved workers from offices that were just facing walls and, you know, didn't have any exposure to natural daylight. And then they did a time period during that study where they actually were in front of a window and working. And they measured their sleep and their sleep time and their sleep efficiency increased quite dramatically.

• 46:20Speaker 07

  I'm forgetting the numbers now, but I think the increase in total sleep time is well over thirty minutes. And the improvement in sleep efficiency was five to ten percent. You know, and if you're batting an eighty percent, you know, sleep efficiency average, we're a bit concerned about that. But. Add 10% to that. Now you're in, you know, a great echelon of healthy sleepers. And all you did was just spend some time working in front of windows.

• 46:45Andrew D. Huberman?

  That's great. And probably, um, folks might want to consider spending a little less time with sunglasses, provided they can do that safely, you know, driving, et cetera. You're not alone with your exercise behavior and facing east. So, um, the one and only Tim Ferriss told me recently that his morning routine nowadays consists of jumping rope while facing east to get the sunlight stimulation of the eyes. And, um, as Matt and I both know, it has to be of the eyes, right? I mean, these portals are the only way to, um, convey to the rest of the brain and body about the time of day and wakefulness. Um, along the lines of wakefulness, I have a number of questions about caffeine. Yeah. The dreaded and beloved caffeine. I love caffeine,

• 47:29Andrew D. Huberman?

  but I like it in relatively, um, restricted periods of time. So, um, I'm a big fan of waking up and even though I wake up very groggy, allowing my natural wakefulness signals to take hold, meaning I wake up very slowly, but I don't drink caffeine right away. I've sort of delayed caffeine by a little while, usually 90 minutes to two hours.

• 47:54Speaker 07

  Okay.

• 47:55Andrew D. Huberman?

  And that idea came to me on the basis of my understanding of how caffeine and the adenosine receptor interact. I have a feeling you're going to pronounce adenosine differently than I do.

• 48:05Speaker 07

  No, no, no. I will go with, I'll go with the denosine.

• 48:07Andrew D. Huberman?

  I'll, I'll try to go with your skeletal instead of skeletal and synapse and synapse.

• 48:12Speaker 07

  Schedule and schedule.

• 48:14Andrew D. Huberman?

  There we go. But, um, but to make it really simple for folks, how does caffeine work to make us feel more alert? And does the timing in which we ingest caffeine play an important role in whether or not it works for us or against us? So maybe we just start with, how does caffeine work? Why is it that when I drink mate or coffee, which are my preferred sources of caffeine, do I feel a mental and physical lift?

• 48:41Speaker 07

  Yeah. So I'm going to suggest counter to what most people would think, drink coffee.

• 48:50Andrew D. Huberman?

  Or mate, is mate okay also?

• 48:51Speaker 07

  Yeah, yeah.

• 48:52Andrew D. Huberman?

  Whatever form you enjoy.

• 48:53Speaker 07

  Well, we'll, we'll come on to sort of why I suggest that. But when it comes to coffee, I would say the dose and the timing makes the poison. So let's start with how caffeine works. Caffeine is in a class of drugs that we call a psychoactive stimulants. So it works through a variety of mechanisms. One is a dopamine mechanism. Dopamine, we often think of as a reward chemical or, but dopamine is also very much an alerting neurochemical as well. And caffeine has some role, it seems to play in increasing dopamine.

• 49:33Speaker 07

  But its principal mode of action, we believe, in terms of making me more alert and keeping me awake throughout the day, is on the effects of adenosine. And to explain what adenosine is, from the moment that you and I woke up this morning, this chemical adenosine has been building up in our brain. And the longer that we're awake, the more of that adenosine accumulates.

• 49:56Andrew D. Huberman?

  Is it, um, may I ask, is it accumulating in neurons, in glia, or in the blood vessels? Where and, and is it also accumulating in my body? Where is this adenosine coming from and where is it accumulating?

• 50:09Speaker 07

  Yeah, so the adenosine here that we're talking about, that is creating the sleep pressure, is a central brain phenomenon. And it comes from the neurons themselves combusting energy. And as they're combusting energy, one of the offshoots of that is this chemical adenosine.

• 50:27Andrew D. Huberman?

  Okay.

• 50:27Speaker 07

  And so as we're awake throughout the day and our brain is metabolically very active, it's accumulating and building up this adenosine. Now, the, the more adenosine that we have, the sleepier that we will feel. So it really is like a sleep pressure is what we call it. Now, it's not a mechanical pressure, don't worry, your head's not going to explode. It's a chemical pressure. And it's this weight of sleepiness that we feel gradually growing as we get into the evening.

• 50:59Andrew D. Huberman?

  May I just interrupt you again to just ask, do we know what the circuit mechanism is for that? I mean, not to go too far down the rabbit hole, but for the aficionados and for myself, we have brain mechanisms like locus ceruleus that release things, that are brain areas, locus ceruleus just being a brain area, of course, that release things that create, that proactively create wakefulness.

• 51:21Speaker 07

  Yeah.

• 51:21Andrew D. Huberman?

  So are those neurons shutting down as a consequence of having too much adenosine? Or are there areas of the brain that promote sleepiness that are becoming activated? Because these, you can imagine both things working in parallel. One or the other would accomplish the same endpoint.

• 51:37Speaker 07

  Yeah, and it's, it's both. And so there are two main receptors for adenosine, the A1 receptor and the A2 receptor. And they have different modes of activating brain cells or inactivating or decreasing the likelihood of firing. And adenosine works in this beautiful elegant way where it will inhibit and shut down the wake promoting areas of the brain whilst also increasing and dialing up the volume on sleep activating, sleep promoting.

• 52:10Andrew D. Huberman?

  Biology is so beautiful.

• 52:11Speaker 07

  Oh, it's fantastic.

• 52:13Andrew D. Huberman?

  I mean, and we could have a larger discussion at some point about that, everything, seeing dark edges, seeing light edges.

• 52:19Speaker 07

  Yeah.

• 52:20Andrew D. Huberman?

  Our ability to, to smell or to sense pressure on this, everything's a push.

• 52:24Speaker 07

  Oh, it's great. Yeah, yeah.

• 52:25Andrew D. Huberman?

  So this is another example where as I am awake longer, adenosine is released in the brain and my wakefulness areas are being actively shut down by that adenosine and my sleepiness brain areas, so to speak, are being promoted to be more active. Is that correct?

• 52:43Speaker 07

  That's right. And it's a very progressive process. It's not like a step function where, and sometimes that happens occasionally, but it's usually because you've been sort of driving through and as we'll come on to have caffeine in the system. And then all of a sudden you just hit a wall and it just, you know, engulfs you and you go from a zero to the one of sleepiness within a short period of time.

• 53:04Andrew D. Huberman?

  What explains the fatigue after a hard conversation? The desire to go to sleep or the desire to go to sleep during a hard conversation.

• 53:12Speaker 07

  Um, that's an interesting one. I think it's usually just based on personality type interactions. And for the most part.

• 53:18Andrew D. Huberman?

  Not that I've ever experienced that.

• 53:19Speaker 07

  No, people with you don't, but with me, they almost.

• 53:22Andrew D. Huberman?

  No, no, no, I mean, I've experienced the desire to, to some conversations. I'm halfway through them and I feel like I want to take a nap.

• 53:30Speaker 07

  Yeah.

• 53:30Andrew D. Huberman?

  Right?

• 53:31Speaker 07

  Um, and I would love to look at, you know, people's sleep history. We've sort of seen that time and time again, but, um, and then it could be, you know, with, with folks like me, people just lose the will to live within about five minutes of speaking with me. So.

• 53:43Andrew D. Huberman?

  Not true. They hear that sleep is important. That's all.

• 53:46Speaker 07

  And that's flattery. That's great. But so the way that then caffeine comes into this, um, equation, as I was saying, it's usually a kind of a linear process, or maybe it's probably closer to an exponential in terms of your subjective feeling of sleepiness. Um, and we haven't really been able to measure that in humans because normally we, it's hard to actually, you know, stick something into the brain and be, you know, sucking, siphoning off stuff every couple of minutes, as you could do in animal studies, and keep asking people every couple of minutes, how sleepy do you feel? How sleepy? And track to see if there's a linear rise in, you know, adenosine, which then creates an exponential rise in subjective sleepiness or what the dynamics are. But I'm, I'm kind of nerding out.

• 54:30Speaker 07

  Caffeine comes into play here because caffeine comes into your system and it latches on to those welcome sites of adenosine, the adenosine receptors. But what it doesn't do is latch on to them and activate them. Because if it was doing that, then it would, you know, in lots of ways, it would dial up more sort of sleepiness. It does the opposite. The way that caffeine works is that it comes in, competes with quite sharp elbows with adenosine competitively, forces them out of the way, hijacks that receptor by latching on to it, but then just essentially blocks it. It doesn't inactivate the receptor. It doesn't activate the receptor. It.

• 55:17Speaker 07

  Functionally inactivates it in the sense that it takes it out of the game for adenosine. So it's it's like someone, you know, coming into a room and you're just about to sit down on the chair and caffeine comes in and just pulls out the chair and you're like, well, now I've got nowhere to sit. And caffeine just keeps pulling out the chairs from adenosine. And adenosine, even though it's at the same concentration in your brain, your brain doesn't know that you've been awake for, you know, 10 hours, 16 hours at that point when you've downed a cup of coffee, because all of that adenosine that's still there can't communicate to the brain that you've been awake for 16 hours.

• 56:00Andrew D. Huberman?

  But the adenosine is still in brain circulation.

• 56:03Speaker 07

  Correct.

• 56:04Andrew D. Huberman?

  So the real question is what happens when caffeine is dislodged from the adenosine receptor?

• 56:09Speaker 07

  Unfortunate things happen, and that's what we call the caffeine crash, which is caffeine has a half-life and it's metabolized.

• 56:16Andrew D. Huberman?

  Do you recall what the half-life is?

• 56:18Speaker 07

  Yeah, the half-life is somewhere between five to six hours and the quarter-life therefore is somewhere between 10 to 12 hours. It's variable. Different people have different durations of its action, but for the average adult, five to six hours. That variation we understand it's down to a liver enzyme or a set of liver enzymes of the class that we call the cytochrome P450 enzymes. And there are two, I think last I I delved into the data, which is pretty recently, there are two gene variants that will dictate the enzymatic speed with which the liver breaks down caffeine. And that's why you can have some people who are very sensitive to caffeine and other people who say, you know, I'm just,

• 57:02Speaker 07

  it doesn't affect me really that much at all.

• 57:04Andrew D. Huberman?

  These are the people that have a double espresso after a 9pm dinner and can sleep just fine.

• 57:08Speaker 07

  Well, and we'll come on to-

• 57:09Andrew D. Huberman?

  Or at least objectively, they think they're sleeping.

• 57:11Speaker 07

  Subjectively, yeah. And we should speak about that, that assumptive danger too. So then the caffeine is in the system and after some time period, it will be inactive in the system. So let's say that, you know, I've been awake for- Twelve hours now and it's, you know, eight P M and I'm feeling a bit tired, but I want to push through and I want to keep working for another couple of hours. So I have a cup of coffee. All of a sudden I was feeling tired, but I don't feel like I've been awake for 12 hours anymore. Because with the caffeine in the system, maybe only half of that adenosine is being communicated through the receptor to my brain.

• 57:51Speaker 07

  A hundred percent of the the adenosine is still there. Only half of it is allowed to communicate to my brain. So now I think, oh, I haven't been awake for 12 hours. I've just been awake for six hours. I feel great. Then after a few hours and the caffeine is starting to come out of my system. Not only am I hit with the same levels of adenosine that I had before I'd had the cup of coffee several hours ago. It's that plus all of the adenosine that's been building up during the time that the caffeine has been in my system.

• 58:22Andrew D. Huberman?

  Sort of a an avalanche of.

• 58:24Speaker 07

  It is a tsunami wave. Yeah. And that's the caffeine crash.

• 58:27Andrew D. Huberman?

  And it's interesting because the caffeine crash at two o'clock in the afternoon, when you have work to do is a terrible thing, but what about the person? Maybe this person is me in my twenties who says, I'm gonna drink caffeine all day long. And then I want the crash because at nine or 10 P M, if I stop drinking caffeine at, say, six P M. And I crash, then I crash into a slumber, a deep night of sleep.

• 58:54Speaker 07

  Yeah.

• 58:54Andrew D. Huberman?

  Is that sleep really as deep as I think it is? Because given the half life of caffeine that you mentioned a few moments ago. I have to imagine that having some of that caffeine circulating in my system might disrupt the depth of sleep or somehow the architecture of sleep in a way that even if I get eight or who knows even 10 hours of sleep. It might not be as restorative as I would like it to be.

• 59:18Speaker 07

  Yeah. And that is the danger, just sort of that, you know, those people that you described who say, and I, a lot of them will speak with me too. Say, look, I can have two espressos with dinner and I fall asleep fine and I stay asleep. Because usually those are the two phenotypes that we typically see with too much caffeine. I just can't fall asleep as easily as I want to, or I fall asleep, but I just can't stay asleep. And caffeine can do both of those things quite potently.

• 59:43Andrew D. Huberman?

  How late in the day do you think is, assuming somebody, translate this, folks, if you go to bed earlier or later, you have to shift the hours accordingly, but given somebody who typically gets into bed around 10, 10:30 and falls asleep around. Uh, eleven, eleven thirty.

• 59:58Speaker 07

  Yeah.

• 59:59Andrew D. Huberman?

  When would you recommend they halt caffeine intake? And these are not strict prescriptives, but I think people do benefit from having some fairly clear guidelines of what might be, might work for them. Would you say cut off caffeine by what time of the day?

• 1:00:16Speaker 07

  I would usually say, take your typical bedtime and count back sort of somewhere between ten to eight hours is probably getting a little bit close, but take back sort of ten hours or eight hours of time. That's the time when you should really stop, you know, using caffeine is the suggestion. And the reason is because for those people who even just keep drinking up until, you know, the, into the evening, you're right that they can fall asleep fine, maybe they stay asleep, but the depth of their deep sleep is not as deep anymore. And so there are two consequences. The first is that for me, and it can be up to by thirty percent, and for me to drop your deep sleep by thirty percent, I'd have to age you by between ten to twelve years.

• 1:01:00Speaker 07

  Or you can just do it every night to yourself with a couple of espressos. The second is that you then wake up the next morning and you think, well, I didn't have problems falling asleep and I didn't have problems staying asleep, but I don't feel particularly restored by my sleep. So now I'm reaching for three or four cups of coffee the next morning, rather than just two or three cups of coffee. And so goes this dependency cycle that you then need your uppers to wake you up in the morning. And then sometimes people will use alcohol in the evening to bring them down because they're overly caffeinated. And alcohol, and we can speak about that too, also has very deleterious impacts on your sleep as well.

• 1:01:41Speaker 07

  So you're right that it's not just the quantity of your sleep or even difficulties falling or staying asleep, it can also be deep sleep. But here again, I think, you know, I don't want to be frightening people. And I mentioned this before, I think one of the real problems that I, or mistakes that I made, because I didn't, you know, I'd never had much public exposure before the book.

• 1:02:05Speaker 07

  And I was so saddened by, you know, the disease and the suffering that I was seeing as a consequence of a lack of sleep in our society. And the fact that it wasn't really being discussed very much. I sort of came out, you know, a little bit headstrong, more than a little bit headstrong. And I think I was, you know, perhaps too, too much gas pedal and too little, you know, brake, as it were. And I don't think that's the right way to approach health message within the public sphere. And I've become much softer in how I think about these things. I have ideas about what the ideal world looks like for sleep.

• 1:02:49Speaker 07

  But I also realize that none of us live in this thing called the ideal world.

• 1:02:53Andrew D. Huberman?

  We certainly don't.

• 1:02:53Speaker 07

  So, you know, I want to be really mindful of that. And I think I've done a really bad job of being sort of too forthright, particularly for people who struggle with sleep. You know, early on, when I would offer these sort of messages about sleep, I want to be, you know, I want to be veridical when it comes to the science. I want to be faithful to the science. But I also don't want to go out and scare the living daylights out of people, particularly people who are struggling with their sleep, because it's probably only going to make matters worse. So I've been beautifully schooled by learning how to be a slightly better public communicator. I'm nowhere near of the standing that, that you are. You're very elegant and it's very intuitive to you. I'm still with training wheels, but I'm getting a little bit better.

• 1:03:37Speaker 07

  But I don't, I just want to say that when I'm speaking about caffeine, because it sounds as though I'm very sort of overt about it. But I will come back to why I say drink coffee. But I just want to make that point.

• 1:03:49Andrew D. Huberman?

  Yeah, well, I appreciate you making that point, and I'm sure our listeners will too. I, I still will stand behind my statement, which is that what you've done for the notion that sleep is vital for all aspects of health and for performance, mental and physical and wakefulness. The message and the, and the packaging it was contained in and is, has been clearly, clearly net positive. People needed to be cued to this. The I'll sleep when I'm dead mentality is one that I had. It's one that other people have. People in a huge number of vital communities, not just your students, but also people. The messaging that you provided and continue to provide has positively impacted the first responder

• 1:04:34Andrew D. Huberman?

  community, the medical community. There's still steps that need to be taken, the military community, and of course, the civilian community. And so I think these adjustments about, yeah, caffeine's okay, just restrict it to the early part of the day if you can, most days. I mean, I think the law of averages. It's like the light viewing behavior. I think it is critical to view sunlight or natural, some other form of bright light early in the day. But if you miss a day, it's not that your whole system is going to dissolve into a puddle of tears. That'll happen on the second or the third day. No, I'm kidding. You get a couple of days. Biology works in averages, except with respect to accident or injury. A car accident is a car accident, right? You don't get to have three of those before the brain damage occurs if

• 1:05:16Andrew D. Huberman?

  the accident is severe enough. But with sleep behavior, these homeostatic type behaviors, or with food, one chocolate sundae, is it going to kill you? No. Every night, yeah, it's going to make you demented and kill you early. We know this. And so I think the the middle ground is often a hard place to achieve. So I think you've done a phenomenal job, but I appreciate you raising these points. And I think it's clear that we all need to, that we all can and should do certain things better, including being gentle with ourselves from time to time when we deviate from these these ideal circumstances. Along these lines, I do want to talk about alcohol, because I think caffeine and alcohol represent the

• 1:05:59Andrew D. Huberman?

  the kind of two opposite ends of the spectrum. Clearly, there are other stimulants. There are your adderalls and your high-energy drinks that people use. But alcohol and caffeine are the most commonly consumed. A stimulant and sedatives, depressants, as they're sometimes

• 1:06:17Andrew D. Huberman?

  What happens when somebody has a glass, we always hear a glass or two of wine in the evening, or a, or a, a cocktail after dinner?

• 1:06:27Speaker 07

  Yeah.

• 1:06:28Andrew D. Huberman?

  Or before dinner? How does that impact their sleep? And then we'll be sure to circle back in terms of what is reasonable ranges of behavior when it comes to avoiding alcohol, or if it's age appropriate, et cetera, enjoying alcohol?

• 1:06:44Speaker 07

  Yeah. So alcohol, if we're thinking about classes of drugs, they're in a class of drugs that we call the sedatives. And I think one of the first problems that people often mistake, alcohol is often used as a sleep aid for people who are struggling with sleep when things like over the counter remedies, et cetera, or herbal remedies have just not worked out for them. And alcohol unfortunately is anything but a sleep aid. The first reason that most people use it is to try and help them fall asleep.

• 1:07:15Andrew D. Huberman?

  So, and this process of, this event that we call falling asleep, I have to imagine is a process.

• 1:07:21Speaker 07

  It is.

• 1:07:21Andrew D. Huberman?

  Like everything in biology.

• 1:07:22Speaker 07

  Yeah.

• 1:07:22Andrew D. Huberman?

  And that that process involves in some way, as we talked about push-pull before, turning off thinking, planning.

• 1:07:29Speaker 07

  Yep.

• 1:07:30Andrew D. Huberman?

  Et cetera, and turning on some sort of relaxation mechanism. I have to imagine that these two things are knobs turning in opposite directions.

• 1:07:37Speaker 07

  That's right.

• 1:07:37Andrew D. Huberman?

  That gives us this outcome we call falling asleep. Alcohol, it seems, is helpful for some people to turn off their thoughts or their planning. Is that right?

• 1:07:48Speaker 07

  Yes, it is. And so I think, you know, if we look at the pattern of brain activity, if I were to place you inside an MRI scanner where we're looking at the activity of your brain and what you drifting off, some parts of your brain will become less active, other parts will become more active. And this is the push-pull model. It's inhibition, excitation.

• 1:08:08Speaker 07

  But alcohol is quite different in that regard. Alcohol is because it's a sedative. What it's really doing is trying to essentially knock out your cortex. It's sedating your cortex. And sedation is not sleep. But when we have a couple of drinks in the evening, when we have a couple of nightcaps, we mistake sedation for sleep, saying, well, I always, when I have like a couple of whiskies or a couple of cocktails, it always helps me fall asleep faster. In truth, what's happening is that you're losing consciousness quicker, but you're not necessarily falling naturalistically asleep any quicker. So that's one of the first sort of things just to keep in mind. The second thing with alcohol is that it fragments your sleep.

• 1:08:52Speaker 07

  And we spoke about the quality of your sleep being just as important as the quantity. And alcohol, through a variety of mechanisms, some of which are activation of that autonomic nervous system, that fight or flight branch of the nervous system. Alcohol will actually have you waking up many more times throughout the night. So your sleep is far less continuous. Now, some of those awakenings will be of conscious recollection. The next day, you'll just remember waking up. Many of them won't be. And so, but yet your sleep will be littered with these sort of punctured awakenings throughout the night. And again, when you wake up the next morning, you don't feel restored by your sleep.

• 1:09:36Speaker 07

  You know, fragmented sleep or non-continuous sleep in this alcohol-induced way is usually not good quality sleep, but you feel great on the next day. The, the third part of alcohol in terms of an equation is that it's quite potent at blocking your REM sleep, your rapid eye movement sleep. And REM sleep is critical for a variety of cognitive functions, some aspects of learning and memory, seems to be critical for aspects of emotional and mental health.

• 1:10:04Andrew D. Huberman?

  You've described it before as a sort of self-generated therapy that occurs while we sleep.

• 1:10:09Speaker 07

  Yeah, it's overnight therapy. You know, it's emotional first aid.

• 1:10:13Andrew D. Huberman?

  Certainly, people that don't get enough sleep are very easy to derail emotionally.

• 1:10:18Speaker 07

  Yeah.

• 1:10:19Andrew D. Huberman?

  Not that one would want to do that to people, but we all sort of fall apart. Emotionally, I always think about almost like our skin sensitivity can be heightened.

• 1:10:28Speaker 07

  Yes.

• 1:10:28Andrew D. Huberman?

  When we are sleep deprived. Our emotional sensitivity is such that when we're sleep deprived, such that it takes a much finer grain of sandpaper to create that kind of friction. Things bother us.

• 1:10:44Speaker 07

  Threshold.

• 1:10:44Andrew D. Huberman?

  Even online comments bother us when we're sleep deprived. And never when we're well rested.

• 1:10:50Speaker 07

  I would love to say that I never look at them, except I look at.

• 1:10:54Andrew D. Huberman?

  Here I will editorialize because the notion of not looking at comments is unreasonable for to ask of any academic because academics, we are all trained to look at our teaching evaluations. And just like with online comments, to ignore 20% of them. No, I'm kidding. We look at them all. In any event, so in terms of translating this to behavior, I'm not, I don't particularly enjoy alcohol. I guess I might be fortunate in that sense, but I also have never really experienced the pleasure of drinking alcohol. I sometimes like the taste of a drink, but I never liked the sensation. So that's, I don't have a lot of familiarity with this, but many people do, and I understand that.

• 1:11:36Andrew D. Huberman?

  So let's say somebody enjoys a glass of wine or two with dinner and they eat dinner at 7:00 PM. Is that likely to disrupt their sleep at all? Let's just sort of, let's make this a series of gradations.

• 1:11:51Speaker 07

  Yeah, and the answer is yes. I think once they just looked at a single glass of wine in the evening with dinner and I would be untruthful if I didn't just simply say it has an effect and we can measure that in terms of.

• 1:12:08Andrew D. Huberman?

  Less REM sleep.

• 1:12:09Speaker 07

  Less REM sleep. And one of the fascinating studies, I can't remember what dose, I think they got them close to a standard illegal blood alcohol level. So maybe they were a little bit tipsy. And yes, you see all of the changes that we just described. They sort of lose consciousness more quickly, they have fragmented sleep and they have a significant reduction in REM sleep. But what was also interesting because. REM sleep, as we spoke about before, is a time when some hormonal systems are essentially recharged and refreshed, growth hormone being one of them. There was well over a 50%, five zero drop in their growth hormone release during alcohol laced sleep at night.

• 1:12:51Andrew D. Huberman?

  Wow. And growth hormone is so vital for metabolism and repair of tissues and

• 1:12:55Speaker 07

  Yeah.

• 1:12:56Andrew D. Huberman?

  Keeping body fat low.

• 1:12:58Speaker 07

  Essentially, adults.

• 1:12:59Andrew D. Huberman?

  Essential. Along those lines, I just want to highlight the fact that this

• 1:13:06Andrew D. Huberman?

  this information that you're sharing, that growth hormone is released is strongly tethered to the presence of healthy amounts of REM sleep is interesting to me because I always thought that growth hormone was released in the early part of the night.

• 1:13:19Speaker 07

  Well, it is released across both of those, but across the different stages. But what we also know is that when you disrupt REM sleep, there are those growth hormone consequences.

• 1:13:30Andrew D. Huberman?

  I see.

• 1:13:30Speaker 07

  So it's not an exclusive system, just like with testosterone. We can see changes throughout non REM sleep. But if you ask, when are the peak release rates of testosterone? It's right before we go into REM sleep and then during REM sleep.

• 1:13:45Andrew D. Huberman?

  And of course, testosterone being important, both for males and for females, right? For libido and tissue repair and wellbeing. Nobody, regardless of chromosomal hormonal or any other background, wants to have their normal levels of testosterone reduced acutely. That's just a bad, it equates to a terrible set of psychological and physical symptoms.

• 1:14:07Speaker 07

  Yeah, and the mortality risk that's associated with low testosterone is non trivial.

• 1:14:11Andrew D. Huberman?

  Prostate cancer.

• 1:14:12Speaker 07

  Right, exactly. You know, so

• 1:14:15Speaker 07

  coming back to just the point on REM sleep that you mentioned regarding emotional instability. And we see that, that's one of the things, one of the most reliable signatures of just insufficient sleep, doesn't have to be sleep deprivation. What we've discovered over the past 20 years here at the Sleep Center is that there is no major psychiatric disorder that we can find in which sleep is normal. And so I think that firstly told us there is a very intimate association between your emotional, mental health and your sleep health.

• 1:14:48Speaker 07

  But when it also comes to REM sleep, I think what's fascinating is that it's not just about your emotional health, it's not just about your hormonal health. We've also been seeing other aspects of cognition. But then there was a report, I think it could have been about two years ago, out of Harvard, I think it was Beth Kliman's group, they found that, and they replicated it in two different large populations, if you look at the contribution of different sleep stages to your lifespan, REM sleep was the strongest predictor of your longevity. And it was a linear relationship, it wasn't sort of one

• 1:15:32Speaker 07

  of these U-shaped or J-shaped curves that we often see with total sleep and mortality risk. It really was linear, that the less and less REM sleep that you were getting, the higher and higher your probability of death. And then they did-

• 1:15:46Andrew D. Huberman?

  Was that death due to natural causes or accident? Because I could imagine if you're not getting enough REM sleep, you're more likely to drive off the freeway, step off a cliff-

• 1:15:54Speaker 07

  Yeah, I think it was all cause-

• 1:15:55Andrew D. Huberman?

  Or just make bad decisions about anything, in love, relationships-

• 1:15:57Speaker 07

  Yeah.

• 1:15:58Andrew D. Huberman?

  Which can also be life threatening.

• 1:16:00Speaker 07

  Yeah, I've tried to lean into that and claim that I, with those bad relationship situations, that, oh, I just didn't have enough REM sleep last night, my darling-

• 1:16:07Andrew D. Huberman?

  The REM sleep defense.

• 1:16:08Speaker 07

  Yeah. And, but she's far wiser than I thought. But, so, they did this great machine learning analysis, and I may get these numbers backwards, but I think for every 5% reduction in REM sleep, there was a 13% associated increased risk of mortality.

• 1:16:29Andrew D. Huberman?

  Wow.

• 1:16:30Speaker 07

  And I could have, I'll have to go back and check. But to me, and in the machine learning algorithm, what they ultimately spat out was that of all of the sleep stages, REM sleep is the most predictive of your longevity, of your lifespan. So we often, I hear people saying, how can I get more deep sleep? Or they sometimes say, how can I get more dream sleep? And my answer is a question. Why do you want to get more of that? And they'll say, well, isn't that the good stuff? And I'll say, well, actually, all stages of

• 1:17:02Andrew D. Huberman?

  It's all the good stuff.

• 1:17:03Speaker 07

  Yeah.

• 1:17:04Andrew D. Huberman?

  Well, it's like the exercise question. And it took decades for people to understand that moving around at for about 150, probably 180 minutes a week at doing endurance type work, zone two cardio type work is correlated with living longer, feeling better, less diabetes, et cetera. There's really no way around it. I mean, you can, you can ingest metformin until the cows come home. You can take NMN, all of which I think have their place in certain contexts. I'm a big fan of the work surrounding all those protocols.

• 1:17:38Speaker 07

  Likewise.

• 1:17:38Andrew D. Huberman?

  But without getting proper amounts of movement, meaning sufficient numbers of, it doesn't matter how many 12 minute exercise regimes you follow per week, you need that threshold level. And it sounds like the same is true of REM sleep and total amount of sleep. There's just, you, you pay the piper somehow.

• 1:17:59Speaker 07

  Yeah, the return on investment, I mean, to flip the coin, the return on investment is astronomical. You know, I think of sleep, it is the tide that moves, you know, that raises all of those health boats.

• 1:18:12Andrew D. Huberman?

  And the most fundamental layer of mental and physical health. Whenever people ask me, even though I'm not a physician, they'll ask me, what should I, what should I take? Or what should I do? The first question is always, how's your sleep? Meaning, how well do you sleep every night? And how, how long are you sleeping? I always recommend your book. I always recommend your podcast, you know, the podcast you've been a guest on, et cetera.

• 1:18:35Andrew D. Huberman?

  Who knows, maybe you'll even release your own podcast at some point soon and keep, because I do think people need to hear from you more often. One thing, I, I don't want to return to the, the notion of, of public health discourse too much, but I do want to say, one issue with books in general is that They can be revised, but it's more or less a one and done kind of thing until the next book comes out.

• 1:18:56Speaker 07

  Yeah.

• 1:18:57Andrew D. Huberman?

  One thing that I like about the podcast format is that updates can be provided regularly, corrections and updates as new data come out. And so that's a wonderful aspect to this format and, and hopefully the format that you'll be embracing. I think the world needs to hear more from you more often about sleep and its various contours, not less. And so I do have a question about drinking alcohol.

• 1:19:23Speaker 07

  Yeah.

• 1:19:24Andrew D. Huberman?

  Not that we want to promote day drinking, but let's say that the one or two glasses of wine or a cocktail is consumed with lunch, something that isn't traditionally done nowadays. Or in a late afternoon, happy hour cocktail. And then one is going to sleep seven or eight hours later. Do you think that that will improve or somehow mitigate the effects of alcohol? Or if you have a drink, are you, are you basically screwed for the next 24 hours?

• 1:19:52Speaker 07

  No, I think there's going to be a, a time window dependency. Now, I don't know of anyone who's essentially done what you and I would like, which is the time separation dose dependent curve where, okay, you drink at 10 a.m. then, or 11, 12, 1, 2, 3, 4, 5, all the way up to, you know, 10 p.m. And estimate what is the blast radius? And is it linear or is it nonlinear? Is it such that only when you drink in the last four hours, do you just hit this exponential and it's bad, bad, bad? Or is there some other curve that we could imagine? There would be many possibilities. But certainly what we know is that the less alcohol and the less, and more specifically,

• 1:20:37Speaker 07

  the metabolic byproducts, aldehydes and ketones, the, the sort of the nefarious players.

• 1:20:43Andrew D. Huberman?

  And not the ketones that people are all excited about, the other, the other ketones.

• 1:20:47Speaker 07

  Yes.

• 1:20:47Andrew D. Huberman?

  The chemists, the chemists know what we're referring to.

• 1:20:49Speaker 07

  Yeah, this is not about ketogenesis.

• 1:20:50Andrew D. Huberman?

  This is not about ketogenesis. There are ketone bodies and, uh, that are released, uh, after ingesting alcohol that are not of the positive sort.

• 1:20:59Speaker 07

  Correct.

• 1:20:59Andrew D. Huberman?

  That a ketogenic diet might promote.

• 1:21:01Speaker 07

  Right.

• 1:21:02Andrew D. Huberman?

  Yeah.

• 1:21:02Speaker 07

  So I think in terms of that alcohol, um, profile, we certainly know that, you know, as you're heading into the evening hours, once again, timing and dose make the poison. But I think it's also important, once again, from that public message standpoint. And thank you, I think I am leaning into the sort of the podcast consideration arena at some point, but I don't want to be puritanical here, you know, I'm just a scientist and I'm not here to tell anyone how to live. All I'm trying to do is empower people with some of the scientific literature regarding sleep and then you can make whatever informed choices that you want. Now, unlike you, it turns out I'm not a big drinker.

• 1:21:47Speaker 07

  It's just because I've never liked the taste and I'm surprised that they haven't taken away my British passport because I don't like lager or beer. But I also want to say that life is to be lived to a certain degree. It's all about checks and balances. So, you know, if I go out and, you know, I have an ice cream sundae, I'm not big on those either, but you know, sure, I know that my, you know, blood glucose is not going to be ideal for another 12 hours, maybe. That's just the price you pay for having some kind of relaxed, fun life. I don't want to look back on life and think, gosh, you know, I lived until I was, you

• 1:22:28Speaker 07

  know, 111 and it was utterly miserable, you know.

• 1:22:33Andrew D. Huberman?

  Right.

• 1:22:34Speaker 07

  So, but it's all about some kind of a balance and my, my job is not to, to tell people a prescription for life, it's just to offer some scientific information.

• 1:22:43Andrew D. Huberman?

  I think you're doing a terrific job of that. People are, I always say, we have all these neural circuits and if it's working properly, we all have a circuit that allows us to skip over information or as we wish, right? If the circuits between your brain and your thumbs are working, you can slide right along, you can drop to the next content, however you like. I, I would like to ask about marijuana and CBD. This is a discussion that I think five years ago would have ventured into the realm of illegal, but now

• 1:23:12Speaker 07

  Yeah.

• 1:23:13Andrew D. Huberman?

  in many places, not all, medical marijuana is approved or is legal and certainly it's in widespread use. Certainly not recommending people do it. I have my own thoughts about marijuana CBD. I've been fortunate, I suppose, that I don't particularly like marijuana or CBD. I don't even know if I've ever tried CBD. First of all, does marijuana disrupt the depth of sleep, the architecture of sleep? And if so, As with alcohol and caffeine, does when you ingest it or when it's in your bloodstream, does relative to when you go to sleep, does that play an important role? So, does marijuana disrupt sleep?

• 1:23:56Speaker 07

  Yeah, it does. And there's a pretty good amount of data on. So, we can break cannabis down into two of its key ingredients. We've got THC, tetrahydrocannabinol, and we've got CBD. And CBD is sort of the less, what we think of as the non-psychoactive component. In other words, when you take CBD, you don't get high. If you take THC, you can get high. That's the psychoactive part of the equation.

• 1:24:28Andrew D. Huberman?

  Are both considered sedatives in the technical sense?

• 1:24:31Speaker 07

  No, they're not. Neither of them have that class right now. THC can, seems to speed up the time with which you fall asleep. But again, if you look at the electrical brainwave signature of your falling asleep with and without that THC, it's not going to be an ideal fit. So, you could argue it's non-natural. But many people use THC for that fact because they find it difficult to fall asleep. And it can speed the onset of at least non-consciousness, I guess is the best way of describing it. But there are problems with THC, and there are two folds. The first is that it too, but through

• 1:25:15Speaker 07

  different mechanisms, seems to block REM sleep. And that's why a lot of people, when they're using, will tell me, look, you know, I definitely, I was dreaming, I don't remember, you know, many of my dreams. And then when they stop using THC, they'll say, I was having, you know, just crazy, crazy dreams. And the reason is because there is a rebound mechanism. REM sleep is very clever, and alcohol is the same way in this sense. It's the same homeostatic mechanism. Some people will tell me, look, if I have a bit of a wild Friday night with some alcohol, you know, maybe I'll sleep late into the next morning, and I'll just have these really intense dreams. So, and I thought I wasn't having any REM sleep.

• 1:25:56Speaker 07

  Well, the way it works is that it's during in the middle of the night, really, when alcohol blocks your REM sleep. And your brain is smart. It understands how much REM sleep you should have had, how much REM sleep you have not because the alcohol's been in the system. And finally, in those early morning hours when you're getting through to sort of, you know, six, seven, eight AM. All of a sudden, your brain not only goes back to having the same amount of REM it would have had, it does that, plus it tries to get back all of the REM sleep that it's lost. Does it get back all of the REM sleep? No, it doesn't. It never gets back all of the REM sleep, but it tries. And so you have these really intense periods of REM sleep. Hence, you have really intense bizarre dreams. And that's what happens also with THC.

• 1:26:42Speaker 07

  You build up this pressure for REM sleep, this debt for REM sleep. Will you ever pay it back? Doesn't seem as though you get back everything that you lost. But will you get back some of it? Yes, the brain will start to devour more because it's been starved of REM sleep for so long. But one of the bigger problems with THC that we worry about is withdrawal dependency. So as you start to use THC for sleep, there can be a dependency tolerance. So you start to need more to get the same sleep benefit. And when you stop using, you usually get a very severe rebound insomnia. And in fact, it's so potent that it's typically part of the clinical

• 1:27:27Speaker 07

  withdrawal profile from THC, from cannabis.

• 1:27:32Andrew D. Huberman?

  And there's anxiety withdrawal. I, I, um, I, I, you know, I don't ask anybody to change their behavior. We just, as you said, we try and inform people about what the science says and let them make choices for themselves. People who are regular pot smokers, if you, that many of will insist they're not addicted. And, and maybe indeed, they don't actually follow the profile of classical addiction. I don't know. I'm guessing some do, some don't. But if you ask them, well, what if I took away all marijuana consumption for, I don't know, two weeks? That thought scares many of them and many of them will experience intense anxiety without marijuana, which speaks to perhaps not addiction, but a certain kind of dependency.

• 1:28:16Andrew D. Huberman?

  And again, I, you know, I know many pot smokers, some of whom have jobs that are, that are quite high performing and they, and they manage.

• 1:28:24Speaker 07

  Here in Berkeley, I don't know any of those.

• 1:28:25Andrew D. Huberman?

  Yeah, no, none of those, right.

• 1:28:28Andrew D. Huberman?

  The, what about CBD? I mean, we hear so much about CBD. I've been a little concerned about the fact that the analysis of a lot of CBD supplements out there has confirmed that much like with melatonin, the levels that are reported on the labels in no way, shape or form match the levels that are actually contained in the various supplements. Sometimes the, the levels are much higher than they're reported on the labels. Other times it's much lower. What does ingesting CBD do to the architecture and quality of sleep?

• 1:28:59Speaker 07

  Right now, I don't think we have enough data to make some kind of, you know, meaningful sense out of it. I think the picture that is emerging, however, is probably the following. Firstly, CBD does not seem to be detrimental in the same ways that THC is. So we can start by saying, does it create, you know, potential problems? Not of the, the nature necessarily that we see with THC. But the devil is a little bit in the details from the data that we do have, and it comes onto your valid point of purity. At low dose, CBD can seem to be wake promoting.

• 1:29:41Speaker 07

  So in lower doses, let's say sort of five or 10 milligrams, I'm trying to remember some of the studies off the top of my head. There it actually may enhance wakefulness and cause problems with sleep. It's only once you get into the higher dose range that there seem to have been some, you know, increases, sorry, increases in sleepiness or sort of sedation like increases. And that's usually, I think, above about 25 milligrams as best I can recall from the data. And then when we look in animal models, you typically see the same type of profile too.

• 1:30:19Speaker 07

  So then the question becomes, and now again, you just don't know about, you know, purity. It's very difficult, although I think, and again, I'm not a user, not necessarily because I, you know, have anything against it. It's just that's not, you know, necessarily my cup of tea.

• 1:30:37Speaker 07

  There are some firms that are now doing third-party independent laboratory tests. I don't know how gamed that is, so I've got no sense of it.

• 1:30:45Andrew D. Huberman?

  I think some supplement companies are quite honest and accurate about the amounts of various substances that are in other products and some are not.

• 1:30:54Speaker 07

  Yeah.

• 1:30:55Andrew D. Huberman?

  And I think there's just a huge range. I think the FDA is starting to explore CBD. There are, certainly I saw some grant announcements to explore the function of CBD. Most of the work on CBD is being done by the general public, ingesting it and seeing how they feel. I gave it to my dog who was, had some dementia-related sleep disturbances, and it actually created heightened wakefulness. It completely screwed up his sleep.

• 1:31:17Speaker 07

  It sounds as though it just wasn't.

• 1:31:19Andrew D. Huberman?

  He's a bulldog, so if he's gonna get access to sleep, he's gonna take it.

• 1:31:21Speaker 07

  Okay.

• 1:31:22Andrew D. Huberman?

  Really messed him up, took it away. He did better.

• 1:31:27Andrew D. Huberman?

  But, you know, that's a canine, so.

• 1:31:29Speaker 07

  Right, and it could have been, you know, sort of dose-related too, but.

• 1:31:32Andrew D. Huberman?

  Or binders or other things that are in there.

• 1:31:34Speaker 07

  Correct, yeah, and we, but, but right now, if we were to, and I'm not making this statement, I don't think anyone can make this statement now, but if it ends up being that CBD is potentially beneficial for sleep, how can we reconcile that mechanistically? And I think there are, to me at least, there are at least three candidate mechanisms that I've been exploring and thinking about. The first is that it's thermoregulatory, and what we found in some animal models is that CBD will create a profile of hypothermia. In other words, it cools the body, the core body temperature down, and that's something that we know is good for sleep. The second is that it's an anxiolytic, that it can reduce anxiety.

• 1:32:18Speaker 07

  And that data is actually quite strong, even with some functional imaging work that's been coming out recently, showing that one epicenter of emotion called the amygdala, deep within the brain, is quietened down with CBD. So I think that's at least a second non mutually exclusive, you know, possibility. I think the third is some recent data that's come out that was suggesting that CBD can alter the signaling of adenosine. So it doesn't necessarily mean that you produce more adenosine, but what it can do is perhaps modulate the sensitivity perhaps of the brain, so that the weight of that same adenosine

• 1:32:58Speaker 07

  is weightier in its brain signal, and therefore it creates this stronger pressure for sleep. So I think these are all tentative mechanisms. I think any one of them is viable. I think all three are viable together. But right now, I think, does that sort of help think through the tapestry of THC and CBD?

• 1:33:20Andrew D. Huberman?

  Yeah, very much so. And actually, it's a, it's a perfect segue from, we've talked about caffeine, alcohol, THC, and CBD as sort of, we framed them anyway, as things that, done in moderation at the appropriate times, are probably okay for most people. Certainly not for everybody, there will be differences in sensitivity, but that, done at the incorrect times, and certainly in the incorrect amounts, will greatly disrupt this vital stage of life we call sleep. CBD, it seems, represents a kind of bridge to the topic I'd like to talk about next, which is things that promote more healthy sleep, or somehow contribute to enhancing the architecture and quality of sleep.

• 1:34:03Andrew D. Huberman?

  So I'd love to chat for a moment about The kind of grand, the original, I should say that not the granddaddy, but the OG of sleep supplementation, which is melatonin.

• 1:34:14Speaker 07

  Yeah.

• 1:34:15Andrew D. Huberman?

  The so-called hormone of darkness that's inhibited by light, et cetera. Frame for us melatonin in the context of its naturally occurring form. And then I'd like to talk about melatonin, the supplement, because as in my experience, anytime I say the word melatonin, people think about the supplement melatonin, which in itself is an interesting phenomenon that people are so cued to its role as something you take, we often forget that this is something that we make endogenously. I'd love for you to comment in particular on, even though we, without necessarily getting into its precise nanograms per deciliter values, what are the typical amounts of melatonin that we release each night? And then I'd like to compare that to what is contained in, say, a three milligram or

• 1:34:59Andrew D. Huberman?

  six milligram tablet that one might buy at the pharmacy.

• 1:35:02Speaker 07

  Right.

• 1:35:03Andrew D. Huberman?

  So I go to sleep at night, has melatonin already kicked in before I shut my eyes and lay down my head?

• 1:35:09Speaker 07

  Usually, yes. If your system is working in the correct way, as dusk is starting to happen, so let's say that you look at hunter-gatherer tribes who aren't touched by electricity, and so that's sort of the puritanical state par excellence when it comes to electric light influence. And usually it's as dusk is approaching, that's when melatonin will start to rise. And so when you lose the brake pedal of light coming through the eyes, that normally acts like a hard brake pedal that stamps down and prevents the release and production of melatonin.

• 1:35:49Speaker 07

  As that light brake pedal starts to fade with dusk, then we ease off the brake pedal and melatonin, the spigot of melatonin is opened up and melatonin starts getting released.

• 1:36:02Speaker 07

  And usually we'll see this rising peak of melatonin sometime, usually an hour, two hours later or around, and it varies from different people, around the time of sleep itself, but it's already been on the march for some hours before you actually hit sleep itself.

• 1:36:24Andrew D. Huberman?

  Interesting. And I was always taught, and I'm assuming it's still true, that the only source of melatonin in the brain and body is the pineal gland. Is that still true?

• 1:36:32Speaker 07

  Yeah, it seems to be from best that we can tell. The pineal gland, sort of meaning pea-like sort of shape. It's actually, I think, usually people say it's pea-like. I think if you look at the Latin derivative, it's more, I think it's derived from pine cone, not pea, because in fact, if you look at the pineal, it is more pine cone shaped and so aptly named.

• 1:36:55Andrew D. Huberman?

  Any human brain I've ever dissected, I confess I've dissected a lot because I teach neuroanatomy and have for years. I love looking at the pineal. It's the one structure in the brain that's not on both sides. It's usually pretty easy to find. And it's pretty good size. It looks like a, it looks like a pea. And it's sitting right there. And it's remarkable that it releases this hormone, probably our entire lifespan, and is inhibited by light. The, so our pineal starts to release this into the general circulation. I have to imagine we have melatonin receptors in the brain and body.

• 1:37:27Speaker 07

  Correct. So, yeah. Essentially, your brain has a central master 24-hour clock called the suprachiiasmatic nucleus that keeps internal time. Now, it's not a precise clock if left to its own devices, nothing that a Swiss clockmaker would be proud of. It runs a little bit long and laggy.

• 1:37:48Andrew D. Huberman?

  It's like an American clock.

• 1:37:49Speaker 07

  So.

• 1:37:50Andrew D. Huberman?

  There are a couple of good American watches, by the way. Hamiltons are very nice.

• 1:37:53Speaker 07

  It's very much like a.

• 1:37:54Andrew D. Huberman?

  But we're not famous for our timekeeping or our punctuality for that matter, but the Swiss.

• 1:37:58Speaker 07

  It's very, it's not quite Swiss, like it's more Berkeley like, which is very relaxed. Oh, you know, whatever. So in most adults, the average adult, I should say, your biological clock normally runs a little bit long. It's about about 24 hours and 13 minutes, I think was the last calculation. But the reason that we don't keep drifting forward in time and kind of running consistently, you know, more and later and later, 30 minutes by 30 minutes by 30 minutes each day, is because your central brain clock is regulated by external things such as daylight and temperature, as well as food and activity. All of these

• 1:38:38Speaker 07

  are essentially different fingers that come along and on the wristwatch of the 24 hour clock will pull the dial out and reset it each day to precisely 24 hours. And I make that point because it knows 24 hour time, but it needs to tell the rest of the brain and the body the 24 hour time as well. And one of the ways that it does this is by communicating a chemical signal of 24 hour nus of light and day using this hormone melatonin. And when it is at low levels or it's non-existent, it's communicating the message, it's daytime.

• 1:39:20Speaker 07

  And for us, Dianal species, it says, it's time to be awake. Yet, at nighttime, when dusk approaches and the brake comes off melatonin and we start to release it, then it signals to the rest of the brain and the body, look, it's dusk and it's nighttime. And for us, Dianal species, it's time to think about sleep. So melatonin essentially tells the brain and the body when it's day and when it's night, and with that, when it's time to sleep, when it's time to wake. And therefore, that's why melatonin helps with the timing of the onset of sleep. But it doesn't really help with the generation of sleep itself. And this is why we'll come on to what those studies of supplementation have taught us.

• 1:40:02Andrew D. Huberman?

  So it tells the rest of my brain and body, it's time to go to sleep. It perhaps even aids with the transition to sleep. But it's not going to, for instance, ensure the overall structure of sleep. Or it's not the conductor that's guiding the sleep orchestra, so to speak, throughout the entire night.

• 1:40:19Speaker 07

  Yeah.

• 1:40:20Andrew D. Huberman?

  It's more like the, um, the, the people that essentially take you to your seat and sit you down and give you your program.

• 1:40:26Speaker 07

  Right, exactly. Yeah, sort of the, the, the far less sophisticated analogy I have is, um, you know, melatonin is like the starting official at the 100 meter race in the Olympics.

• 1:40:37Andrew D. Huberman?

  That's a better analogy.

• 1:40:37Speaker 07

  It calls all of the, the sleep races to the line and it begins the great sleep race.

• 1:40:43Andrew D. Huberman?

  Yeah, better analogy, by the way, coming from the sleep researcher of all people.

• 1:40:48Speaker 07

  But it doesn't participate in the race itself. That's a whole different set of brain chemicals and brain, and brain regions. Which then brings us on to perhaps the question of supplementation, which is, is it helpful for my sleep? Will I sleep longer? Will I sleep better? And if I am, what doses should I be taking? Sadly, the evidence in healthy adults who are not older age suggests that melatonin is not really particularly helpful as a sleep aid. I think there was a recent meta-analysis that demonstrated when, um, it, it looked at all of the different sleep parameters.

• 1:41:31Speaker 07

  Melatonin, and a meta-analysis for those not knowing what that is. It's a scientific sort of method that we use where we gather all the individual studies. And we put them in a big bucket and we kind of do this kind of statistical fancy sleight of hand. And we try to come up with a big picture of what all of those individual studies tell us. And what that meta-analysis told us is that melatonin will only increase total amount of sleep by 3.9 minutes on average.

• 1:41:57Andrew D. Huberman?

  Minutes?

• 1:41:58Speaker 07

  Minutes.

• 1:41:58Andrew D. Huberman?

  Not even percent?

• 1:41:59Speaker 07

  No, and it will only increase your sleep efficiency by 2.2%.

• 1:42:05Speaker 07

  So it really

• 1:42:07Andrew D. Huberman?

  This is as, as they say in certain parts of California, that's weak sauce. That's a weak sauce effect.

• 1:42:14Speaker 07

  The, the sauce is not strong, the force is not strong in, in, in this one. When it comes to a, a tool that in healthy people who are not of older age, it doesn't seem to be especially beneficial. Now, you know, results can vary. Everyone is different, of course. So we're talking about the average, the so-called average human adult here.

• 1:42:34Andrew D. Huberman?

  Well, melatonin, in defense of what you're saying, and also I should mention, I have a colleague at Stanford, Jamie Zeitzer, who you know, comes from Chuck Zeitzer's lab at Harvard Med, where he was also trained, a terrific sleep researcher. And I asked him about melatonin and he essentially said the same thing that you just said, which is very little, if any, evidence that it can improve sleep. And yet it's probably the most commonly consumed so-called sleep aid.

• 1:42:57Speaker 07

  Hundreds of million dollars industry.

• 1:42:59Andrew D. Huberman?

  Yeah, so either massive placebo effect, or it's operating through some other mechanism related to quelling anxiety perhaps.

• 1:43:07Speaker 07

  Yeah, that is actually interesting. You know, there are some studies where you do see some, you know, effects. Now, again, when you do the grand average of all studies, it just doesn't seem to have an effect. But let's assume that for some people it does have an effect. Let's not, again, be sort of completely dismissive of that. How could it have that effect? One of the reasons that I've become a little bit more bullish on melatonin from a sleep perspective, and then melatonin more generally for a, maybe we can speak about this too, as a countermeasure when you're undergoing insufficient sleep. There are two, two different routes there. The first reason that I think it could have a sleep benefit for some people is not because it helps in the generation of sleep. We know that it doesn't.

• 1:43:51Speaker 07

  It's because it too seems to drop core body temperature.

• 1:43:55Andrew D. Huberman?

  There it is, temperature again. I'm fascinated these days more and more by temperature as maybe not just a reflection of brain state and wakefulness and in sleep, but actually a lever that is quite powerful.

• 1:44:10Speaker 07

  I think it's both.

• 1:44:10Andrew D. Huberman?

  And with all the interest in ice baths and hot showers and saunas and stuff, something that we will definitely touch on. Temperature variation is so key. So if melatonin is dropping body temperature by a degree or so, something that you've said before can help induce a sleepy state. Maybe that's what's allowing people to get in.

• 1:44:28Speaker 07

  I think that's one possibility. I don't think melatonin by itself will drop it by sort of, you know, a degree, certainly not a degree Celsius. And for order in us to fall asleep and then stay asleep across the night, we do need to drop our core body temperature by about one degree Celsius or about two to three degrees Fahrenheit. And that's why it's always easier to fall asleep in a room that's too cold than too hot. I think that that's one potential avenue that we are considering, thinking more deeply about when it comes to melatonin. And then the other is melatonin as an antioxidant. But let's, I, let me table that for now because I'll just get us sidetracked. That's what we know so far about melatonin

• 1:45:13Speaker 07

  in terms of its supplementation, benefit or lack thereof. Two final points that I shouldn't forget. One is the only population where we typically see some benefit and it often is prescribed is in older adults. Because as we.

• 1:45:27Andrew D. Huberman?

  Older, meaning sixty and older?

• 1:45:29Speaker 07

  Yeah, sixty, sixty-five and older. Because as we get older, you can typically have what's called calcification of the pineal gland, which means that that gland that's releasing melatonin doesn't work as well anymore. As a consequence, they tend to have a flatter overall curve of melatonin release throughout the night. It's not this beautiful, lovely peak and this bullhorn message of it's darkness, please get to sleep. That's why older adults can have problems falling asleep or staying asleep. It's not the only reason by any stretch of the imagination, but it's one of the reasons and it's why melatonin supplementation in those cohorts, older adults, especially older adults with insomnia, people have thought about that as maybe an appropriate use case.

• 1:46:14Andrew D. Huberman?

  Well, along those lines, if we were to compare dosages, I don't, or do we know how much melatonin is typically released into the bloodstream per night? And can we use that as a kind of a rule of thumb by which to compare the typical amount that someone would supplement? I mean, typically, the supplements for melatonin that I see in the pharmacy and elsewhere and online range anywhere from one milligram to 12 or even 20 milligrams. My guess is that a normal night's release of melatonin, typical for somebody in their 20s, 30s, 40s, would be far lower than that. Am I correct or wrong?

• 1:46:52Speaker 07

  Yeah, it's, it's many magnitudes lower, and this is one of the problems, is that I see that too. I see, you know, typical doses are, you know, five milligrams or 10 milligrams. And of course, you know, if you're a supplement company, you know, putting 10 milligrams versus five milligrams, if that's what you're actually doing, which we'll speak about purity as well. You know, it's kind of like the super gulp size, you know, nobody wants to lower price. They just want you to, you know, we'll just give you more for the same price, and that's how we'll compete. So it's been this escalating arms race of melatonin concentration, and it really does not look meaningful for, you know, for sleep in any way.

• 1:47:34Speaker 07

  What we've actually found is that the optimal doses for where you do get sleep benefits in the populations that we've looked at are somewhere between 0.1 and 0.3 milligrams of melatonin. In other words, the typical doses are usually 10 times, 20 times, maybe more than what your body would naturally expect. And this is what we call a supra-physiological dose. In other words, it's far above what is physiologically normal. You know, and to put that in context, imagine I said to you, I want you to eat 20 times as much food today.

• 1:48:12Andrew D. Huberman?

  I thought you were going to use testosterone as example. You know, you're going to take 300 times the normal amount of testosterone. We know that would have. Tons of deleterious effects.

• 1:48:21Speaker 07

  Right.

• 1:48:22Andrew D. Huberman?

  It's terrible.

• 1:48:22Speaker 07

  Yeah.

• 1:48:22Andrew D. Huberman?

  And yet you can do this. Well, one thing that I'm concerned about, about these supraphysiological levels of melatonin is that many years ago, actually here at Berkeley, when I was a graduate student, we would inject animals, which were seasonally breeding animals with melatonin. And the consequence of that was that their gonads, either their testes or ovaries, would shrink many hundred, hundredfold or more. Um, in other words, that they would go from having, um, nice, healthy sized hamster testicles, what a hamster would consider healthy size, um, for a hamster, and they would shrink to the size of a grain of rice. So from like an almonds to a grain, size of a grain of rice. I had to see that only once for me to be very concerned about supraphysiological levels of melatonin.

• 1:49:05Andrew D. Huberman?

  And I realized that melatonin does different things in different species. We are not hamsters. We are not seasonal breeders, uh, seasonally restricted breeders. There might be more breeding during certain seasons. I don't know those data, but nonetheless, hormones are powerful and, and sure, there is an optimal, and sometimes, uh, we see that going slightly above endogenous levels for certain hormones, not always, can have beneficial effects. And sometimes it can have detrimental effects. I'm just concerned about taking high levels of a hormone that has effects on the reproductive axis. And that's one of the reasons why I get very concerned when I see people really getting

• 1:49:46Andrew D. Huberman?

  aggressive about melatonin supplementation, taking a hundred, 10, 500, sometimes even 10,000 times the amount that we would normally release. That's, that's my concern, although it's not nested in any one specific human study. I just, I just don't like to see, I certainly don't want to see other people and I don't want to, uh, personally take a hormone that's known to be androgen suppressive at high levels. Why would I, why would I take that? I, that's the question I ask myself.

• 1:50:15Speaker 07

  I think it's a very, you know, good point. And if you look at some of the evidence around, you know, melatonin's lethality, if you want to go to that extreme, for the most part, you know, it, it's pretty safe.

• 1:50:28Andrew D. Huberman?

  You mean, you can take a lot of it before you die.

• 1:50:31Speaker 07

  Right, exactly. Yeah. But that should not be your yardstick for, because you know, you really need to think about your, you know, your health, not just whether this thing is going to, to kill you or not, as the decision matrix through which you pop a pill.

• 1:50:47Speaker 07

  And it comes on to this concern around melatonin because there was a study, I think it's one that you mentioned too, where they looked at over, I think it was at least over 20 different brands of melatonin supplements. And what they found is that based on what it said on the bottle versus what was in the capsules themselves, it ranged from, I think it was 83% less than what it said on the bottle to 478% more than what it said on the bottle. Now, if you're, if that's a 10 mg, you know, pill, and it's 478% more than 10mg, and we're already at 10mg at many tens of times more than is a physiological,

• 1:51:32Speaker 07

  rather than a supra-physiological dose, we do need to be a bit thoughtful.

• 1:51:37Andrew D. Huberman?

  Yeah, remember those hamsters, folks. Well, and I do appreciate the deep dive on melatonin because I think people need to understand that it's nuanced, it's a matter of dosages and timing, et cetera. And then it may have its place, as you mentioned, in older individuals. And I should mention that I'm an avid consumer of supplements that I believe in for me, and I have been for a very long time. So I'm by no means anti-supplement. Some supplements I refuse to take or avoid taking, others I quite avidly take. And along those lines, I personally, and I don't know what your thoughts on this are, but there

• 1:52:20Andrew D. Huberman?

  are a few things that I've personally found beneficial. I'd love your thoughts on them. And I would love it if you would tell me that everything I'm about to refer to as placebo, that would be fine. So that's what we do. We're scientists, we argue, and then, and then we remain friends in, as it goes.

• 1:52:35Speaker 07

  Always.

• 1:52:36Andrew D. Huberman?

  So magnesium. There are many forms of magnesium. Magnesium citrate is, as we know, is a terrific laxative. Magnesium malate seems, at least from a few studies, seems to relieve some of delayed onset muscle soreness, doesn't seem to create a kind of sedation. Two forms of magnesium that I'm aware of, magnesium biglycinate and magnesium threonate.

• 1:52:56Speaker 07

  Yeah.

• 1:52:58Andrew D. Huberman?

  We believe, based on the data, can more actively cross the blood-brain barrier. So you put it in your gut, but some of that needs to get into your brain in order to have the set of effect. What are your thoughts on magnesium supplementation? Do you supplement with magnesium? And what, what studies would you like to see done if they haven't been done already?

• 1:53:17Speaker 07

  So I don't supplement with magnesium, but I do think three and eight is interesting because of that higher capacity to cross the blood-brain barrier and actually have a central nervous system effect. And the reason that that interests me is because the sleep is by the brain, of the brain, and also for the brain as well as for the body. We just don't have a particularly good set of studies that have targeted exclusively three and eight. We do have lots of studies that have just looked at magnesium in general for sleep. And overall, the data is uncompelling.

• 1:53:53Andrew D. Huberman?

  Interesting.

• 1:53:54Speaker 07

  And for a while, I, I was confused as to why, where did this come from? This kind of myth of magnesium? So I started looking back into the literature, and I've best traced it, at least as far as I can tell, to early studies showing that those who were deficient in magnesium also had sleep problems. They had other problems too, of course, but sleep problems were one of that set of sequelae that came from having lower magnesium. And when they supplemented with magnesium and tried to restore those levels, some of those sleep problems dissipated. And then that seems to have gotten lost in sort of some game of sort of like whispers

• 1:54:38Speaker 07

  around the room, and it's become translated into people who don't have sleep problems, who are healthy sleepers and who are healthy in general, and who have healthy, normal levels of magnesium, if they take more magnesium, they will sleep better. And the data really there is not good. Once again, the only Study that I've seen where magnesium did have some efficacy was in a study with older adults. I think they were sixty to eighty years old. It may have been exclusively women now I think about it. And they also had insomnia. And in that population, you did see some benefits. And my guess is that because it's an older community as well, they were probably, probably deficient in magnesium.

• 1:55:19Speaker 07

  So they fit the former category of simply when you're deficient and you restore, you can help sleep sort of return to normal. But if you are not deficient and you're healthy and you're not old and you don't have insomnia and you're supplementing, thinking that it provides sleep, right now, the data isn't supportive of that. But I just don't think we have enough three and eight data to actually speak about that because it could just be a blood brain barrier issue so far with the other forms.

• 1:55:46Andrew D. Huberman?

  So maybe some additional studies looking specifically at three and eight or bisglycinate would be, would be useful. And magnesium's involved in so many cellular processes, you can imagine that this effect, if it truly exists, is, as we say in science, in the noise, meaning it's in the, it's in the, the jitter of the data, but to isolate the real effect, one needs to do some more refined studies. What are some things that are of interest to you, if not things that you happen to take? These are not things that I personally take, mostly because I just haven't experimented with them. Valerian root is one. Tart cherry and kiwi fruit.

• 1:56:28Andrew D. Huberman?

  Tell me about, tell me about valerian root, tart cherry and kiwi fruit. This is new to me. I mean, I've certainly heard of them and tart cherry and kiwi sounds delicious. But what, what's happening with valerian root, tart cherry and kiwi? And are we talking about eating tart cherries and kiwis and valerian roots? Or are we talking about taking them in pill form?

• 1:56:50Speaker 07

  Usually it's supplements, but it's also both for tart cherries and for kiwis. It's the actual, you know, fruit themselves. Valerian often touted as a beneficial sleep aid and lots of people swear by it too, but the ever Is actually quite against that.

• 1:57:09Andrew D. Huberman?

  Oh, really?

• 1:57:09Speaker 07

  Not that it makes your sleep worse, but of at least the seven good studies that I've been able to find. And typically, these are of the nature of what we call a randomized placebo crossover design. And I won't bore people with what that means. It's sort of one of the.

• 1:57:25Andrew D. Huberman?

  Good study, solid study.

• 1:57:27Speaker 07

  Yeah, it's one of the sort of gold standard methods that we have when we're looking at intervention studies such as drug studies. Five of the seven found no benefit of valerian root on sleep. Then two out of the seven, the data was just insufficient. I think it was a power issue where they just couldn't make any strong conclusions. And then I think there was the most recent um study. I think looked at two different doses of valerian. I could have this wrong. And they just failed to find any effects once again. But the stunning part of that paper, as I recall, they had this big table with all of the different sleep metrics that they looked at.

• 1:58:09Speaker 07

  And there were well over twenty five different things that they tried to see if valerian impacted. And none of them were significant, which stuns me because from statistical probabilities, we know. If you just randomly perform twenty five statistical tests, chances are probabilistically, you'll just get one significant result by random chance. And even with random chance on their side, they still couldn't find a benefit of valerian. So.

• 1:58:37Andrew D. Huberman?

  So valerian root might be worse than nothing at all if there is, so to speak.

• 1:58:42Speaker 07

  I mean, again, placebo effect, we can think about that too. And I would say that if you feel as though it's having a benefit for you. And with all of the caveats that we have with supplements, things like melatonin, purity, concentration, et cetera. You know, maybe it's no harm, no foul, but I'm not a, you know, a medical doctor and I don't tell anyone about. We have all of these disclaimers about not recommending.

• 1:59:04Andrew D. Huberman?

  Sure, and we'll include these. I mean, I always say, you know, we're not physicians. We don't prescribe anything. We're scientists and professors, so we profess things. It's up to people to be responsible for their own health, not just to protect us, but to protect themselves.

• 1:59:19Andrew D. Huberman?

  I do want to hear about tart cherry and kiwi fruit. What's the story there?

• 1:59:25Speaker 07

  Strange, isn't it? I was. You know, I I'm kind of a hard-nosed scientist. And when people, you know, some years ago started saying, oh, tart cherries, it's the thing. Or kiwi fruits, I was thinking, oh, my goodness, this sounds a bit. You've been in California a little too long. Yeah, I know. Yeah, the sun has softened me some. But I thought, look, one of the things that we have to do as scientists is be as open minded as possible. And I should not be so quick to dismiss. So I went to the literature, just started reading as much as I could about it. And there were three really good randomized placebo crossover trials with tart cherries.

• 2:00:04Speaker 07

  And what they found was that in one study, it reduced the amount of time that you spent awake at night by over an hour. And then the other two studies, one of them found that it increased the amount of sleep that you got by thirty four minutes. The other, it increased the amount of sleep that you got by eighty four minutes. Wow. Which, you know, these are, and what's striking is that they were independent studies. I think, meaning that they were from independent groups. And these were, you know, some of these guys, you know, I, I, and girls, I know pretty well. You know, and you know, and trust their work. Right, I really trust their work, too. Were they ingesting actual tart cherries or they're drinking the juice or in capsule?

• 2:00:46Speaker 07

  It was juice. So they, in all three studies, it was juice. Although you can, I think, as a supplement, you can buy it in a capsule. And we've got no idea whether that changes the benefit or not. What was also interesting in, I think it was that last study where they got an increase in sleep by eighty four minutes. It also decreased daytime napping significantly. Well, that's one that I could certainly make use of. I'm, I love my daytime naps, but I'd love to skip them, too. Right. And, and we can speak about naps and the upside and downside of that. Which then made me think, well, if that's the case, maybe the net, net benefit on sleep overall is no different. It's just that it decreases the amount of time that some people were taking to sleep during the day and giving it back to the night.

• 2:01:31Speaker 07

  But that wasn't the case, because if you added the total amount of sleep that they were getting without tart cherries, both naps and nightly sleep combined, still, when you took tart cherries, you still got a net some benefit of total amount of sleep. So, you know, so far. When it comes to supplements and those types of studies, they're good studies and the data looks interesting. But as a drug itself, you know, if this was clinical drug, you know, three studies that are somewhat small in nature and have some positive benefit, that's what we would call preliminary data of maybe a chin scratching kind. So

• 2:02:09Andrew D. Huberman?

  Yeah, and depending on the margins for safety, one might think, well, given that it's a tart cherry as opposed to some pharmaceutical you need a prescription for, then, you know, some people, their threshold to experiment with supplements is quite low. Some people, their threshold is quite high. I feel like, you know, there are two categories, or at least two categories of folks out there. People who hear, oh, tart cherry can improve sleep and will run out and try it. And people who hear, well, that's sounds crazy. Why would I do that? But of course, we have to remind people that tart cherry isn't really what we're talking about, presumably, if this is a real effect, and it sounds like it might be, that there's a compound in tart cherry.

• 2:02:48Speaker 07

  That's right.

• 2:02:49Andrew D. Huberman?

  That if we were to call it whatever, whatever, five alpha six, you know, some molecule, if we refer to it by its technical name, then people would say, oh, that sounds like a very interesting, technical way to approach sleep, but doesn't sound very natural. So both groups are a little bit misguided, in the sense that people who think that everything that comes from naturally occurring foods, plants, etc., things that grow out of the ground, that that's all safe, that's not true. And people that think that pharmaceuticals are the only, if it's not evidence with the purified molecule, then something's not of utility. Well, that's certainly not true. Somewhere in the middle, I think, lies the answer, which is, it sounds to me like tart cherry is at least an intriguing potential

• 2:03:30Andrew D. Huberman?

  sleep aid, intriguing potential sleep aid, and I'm underscoring potential. I'm certainly intrigued by it to the point where I might experiment a bit, but I'm an experimenter for myself. Before I ask you about kiwi, I've had quite good results from taking something called apigenin, which is a derivative of chamomile. But in supplement form, I think I take 50 milligrams about 30 minutes before sleep. And I subjectively experience a

• 2:03:59Andrew D. Huberman?

  A better night's sleep, so to speak. I don't measure, I confess I don't measure my sleep. I'm not a sleep tracker guy. But, you know, there are a few papers out there. They're not what we would call blue, published in blue ribbon journals, but, but they have control groups and it looks somewhat interesting. And there, when I say apigenin, people get somewhat intrigued. Oh, this molecule, chemomile, has long been thought to be a sedative, a mild sedative, but a sedative. Do you drink chemomalt? Do you take apigenin? What are your thoughts on apigenin?

• 2:04:31Speaker 07

  Yeah, I, I don't. And I, I have looked into some of the data regarding sleep as well. Right now, from best I can tell, it's mostly subjective data rather than objective hard sort of sleep measures. And that's why, right now, I, you know, it's sort of unclear, not no comment, but just unclear. Not dismissing it, because I think you and I both ascribe to the idea of absence of evidence is not evidence of absence. So keep your mind open, at least I tell that to myself. I think if you're finding a benefit and you can do what I would think of if I was personally experimenting, which is both the positive and negative parts

• 2:05:13Speaker 07

  of the experiment. What I mean by that is, you know, let's say that I now want to, you know, think about some kind of a sleep supplement. I will take some kind of baseline set of recordings for a month, and I will just gauge where I'm at, sort of supplement free. Then I'll go on for a month to whatever I'm thinking of, of taking, and I don't, you know, supplement. But let's say that I want to and I experiment with that. And I feel as though, based on my metrics, be them objective from my Oura ring, or be them subjective from whatever I'm, you know, writing down in the morning, and both are important and valid, subjective and objective. We like both in the sleep world. And I think, okay, look, it's clearly that it seems to have some kind of an effect.

• 2:05:58Speaker 07

  The key thing, however, is then do the negative experiment, which is now come off it for another month and see, do things get worse? And if I can see that bidirectionality, then I'm starting to think, maybe I'm believing this a little bit more. So that's the way I would sort of typically approach, you know, a supplementation regiment if I were to do it. And that's just me, that's just the way my mind works, but.

• 2:06:24Andrew D. Huberman?

  No, that's great. I think it's very, very scientific and organized in a way that allows you and would allow other people to make very informed decisions for themselves. I like that. I, I like to think in terms of manipulating any aspect of our biology, that behavioral tools always are the first line of entry.

• 2:06:45Speaker 07

  Yeah.

• 2:06:45Andrew D. Huberman?

  Then nutrition, everyone has to eat sooner or later, even if you're fasting. Then perhaps supplementation, then prescription drugs, and then perhaps brain machine interface, devices that you use to induce something. And those could be done in combination. But what concerns me is when I hear people say, well, what should I take without thinking about their behavior, their light viewing behavior, et cetera. But of course, these things work in combination.

• 2:07:09Speaker 07

  Yeah, I think it's, you're right that there's many, when it comes to sleep, there are many low hanging fruits that don't necessarily require you to, you know, put sort of exogenous molecules, in other words, things like supplements into your body, or, you know, use different types of drugs to help you get there. Now, when it comes to prescription sleep aids, I think I've been, again, a little bit too forthright. We know in clinical practice that there may be a time and a place for things like sleeping pills. They are a short term solution to certain forms of insomnia, but they are not recommended for the long term. And we also know that there are lots of other ways that you can get a sleep.

• 2:07:56Speaker 07

  Help or you can get a sleep curative profile from things like cognitive behavioral therapy for insomnia, which is a non-drug approach, psychological.

• 2:08:04Andrew D. Huberman?

  And quite effective, from what I understand.

• 2:08:05Speaker 07

  Very, just as effective as sleeping pills, great data, more effective in the long term. There's a recent study published that after working with that therapist, some of the benefits lasted almost a decade, you know.

• 2:08:16Andrew D. Huberman?

  Amazing.

• 2:08:17Speaker 07

  Now, if you stop sleeping pills, usually you have rebound insomnia where your sleep goes back to being just as bad, if not worse. And I think the same is true when we think about supplementation. There are so many things that are easy to implement when it comes to sleep that don't require venturing out into those waters. And again, we're not here to tell anyone about whether they should venture or not. That's completely your choice. All I'm saying is that if you want to think about optimizing your sleep, there are a number of ways that you can do it that don't necessarily require you to swallow anything or inject anything or, you know, smoke anything or.

• 2:08:53Andrew D. Huberman?

  Right. And for which the margins of safety are quite, quite wide.

• 2:08:57Speaker 07

  Right.

• 2:08:58Andrew D. Huberman?

  That's, that's the other one.

• 2:08:59Speaker 07

  Yes, sorry.

• 2:09:00Andrew D. Huberman?

  So, so speaking of low hanging fruit, I don't know how low it hangs in reality, but what, what about kiwi? They're delicious to me, anyway.

• 2:09:05Speaker 07

  Yeah, the humble kiwi fruit, um, named not, um, shouldn't be mistaken for the, the, the, um, flightless bird of, uh, New Zealand, which is the native bird that we're talking about the kiwi, the fruit here, which, um, those trees and shrubs are, um, mostly, um, Southeast Asia. Kiwi fruits have been previously touted as potentially having a sleep benefit, which again got me curious and I at first threw it out. To my knowledge, there's really only one published human study that's of any value. But what they did find was that it decreased the speed of time with which it took you to fall asleep.

• 2:09:45Andrew D. Huberman?

  These are you ingesting the whole kiwi?

• 2:09:46Speaker 07

  So it's ingesting the whole.

• 2:09:48Andrew D. Huberman?

  With the skin, I eat the skin. People cringe when they see me do it, but don't eat the skin.

• 2:09:52Speaker 07

  No, no, no. I think the idea is some of the good stuff, and I'll come on to this, may actually be in the skin itself.

• 2:09:58Andrew D. Huberman?

  Thank you. You just, you, I just want, you just helped me win a bet. I'll give you your.

• 2:10:02Speaker 07

  Okay, okay. Yeah, you can formulate. By the way, this skin is used. No, no, no. He just told me to say that. So he went. No, he did not. So the skin seems to be part of this potential sleep equation. And that's the, yeah, the, um, you fell asleep faster and you stayed asleep for longer and you spent less time awake throughout the night. And I just thought, well, you know, that's one study. What can you really do with that? There is another study, however, in an animal model, which is, you know, a little bit more interesting. And once again, they found a very similar phenotype that the rats, oh, sorry, they were mice. The mice fell asleep faster and they also spent longer time in sleep.

• 2:10:46Speaker 07

  The sleep duration also increased. What was also interesting mechanistically, and this is not the mechanism that I think ties together tart cherries, kiwi fruit, and, you know, things like melatonin. Cause I think there could be one common binding mechanism. What they found in the animal study is that they could block those kiwi fruit sleep benefits using a GABA blocking agent. Now, GABA, um, GABA, which stands for gamma amino butyric acid is one of the major inhibitory neurotransmitters of the brain. It's kind of like.

• 2:11:22Andrew D. Huberman?

  A naturally occurring sedative, sort of.

• 2:11:24Speaker 07

  Yeah, it's the kind of the red light on the traffic light signal, you know, um, others are green light. GABA is red light. So by playing around with some sort of clever drugs to manipulate the system, they could prevent the benefit of the kiwi fruit by sort of buggering around with the GABA receptor, meaning that perhaps part of the kiwi fruit benefit on sleep was mediated by the brain's natural inhibitory neurotransmitter system called the GABA system.

• 2:11:56Andrew D. Huberman?

  That's exciting.

• 2:11:56Speaker 07

  And I thought that that was, that was kind of, that convinced me a little bit more that maybe there's something here to read into. So. To be determined. Again, here is the banner. But it, you know, tart cherries and kiwi fruits, the data surprised me. Because in part, I was so preoccupied with being, you know, I don't know, a bit purish about it and a bit snobby, thinking, oh, come on, that's definitely not going to work. Well.

• 2:12:25Andrew D. Huberman?

  Compounds are compounds. I look forward to a day when supplements are no longer called supplements, because at the end of the day, whether or not something has an effect, whether or not it's a whole kiwi fruit or a derivative of kiwi fruit, will depend on the molecular compound. And as you mentioned, this potential mechanism via the GABA system. That's I, we both as scientists get excited about mechanism, because when you can trace a mechanism and a pathway, it provides a rationale, a grounding for why kiwi of all things, or tart cherry of all things, might help increase total sleep time. I'd be remiss if I didn't mention or ask about tryptophan and serotonin. I can anecdotally say, when I've taken tryptophan,

• 2:13:07Andrew D. Huberman?

  the precursor to serotonin, or serotonin itself, I have a horrendous night's sleep. I fall asleep very easily, and I experience ridiculously vivid dreams, neither pleasant nor unpleasant, it's kind of a mishmash. And then I wake up and I experience several days of insomnia. That, and I've done the, the positive control and the negative control and all the variations thereof, to confirm that, at least for me, supplementing with serotonergic agents is a bad idea for me.

• 2:13:41Speaker 07

  Yeah.

• 2:13:42Andrew D. Huberman?

  And tryptophan is a common sleep supplement and sleep aid that's discussed. The normal architecture of sleep involves the release of serotonin, but in a very timed and regulated way. What are your thoughts about serotonin in sleep? If you had to kind of put that into a nutshell? And then, why supplementing with serotonin and/or its precursor, tryptophan, might be a good or a bad idea for somebody?

• 2:14:11Speaker 07

  I think one of the potential dangers is that based on what's going on in your body, that can change the absorption of natural sort of tryptophan and serotonin uptake within the brain itself. So I'm always thoughtful when you're playing around with that mother nature dynamic, as it were. The data, as you described, is a little bit all over the map. Some people say that it knocks them out. Other people say, just like you do, it has a terrible impact on my sleep. And when I stop, it's pretty bad for a couple of days. It seems to have this lingering after effect.

• 2:14:52Speaker 07

  I think what could be happening here is we need serotonin to, just as you described, be modulated in very specific ways during the different stages of sleep. If you look at the firing of the brain epicenters where serotonin is released, and there's a bunch of them in the brainstem.

• 2:15:13Speaker 07

  What you find on the release of serotonin too, when we're awake, it's usually in high concentrations. As we start to drift off to sleep, it lowers some, but not necessarily dramatically as we're going into non-REM sleep. But then, when we go into REM sleep, serotonin is shut off. The other, one of the other neuromodulators, noradrenaline, also shut off. REM sleep is the only time during the 24 hour period where we see noradrenaline and serotonin or norepinephrine completely shut down. When I say serotonin, we're also talking 5-HTP, sorry, 5HT. That's just its chemical name here. So whether it, speaking about serotonin or 5HT, it's the same thing.

• 2:15:58Speaker 07

  Norepinephrine, noradrenaline, both of those need to be shut down for you to produce REM sleep. The other, one of the other neuromodulators that then ramps up to produce REM sleep is acetylcholine.

• 2:16:12Speaker 07

  So these three neuromodulators have this incredible reciprocal dance that they have for you to generate what is called a natural architecture of sleep throughout the night.

• 2:16:23Andrew D. Huberman?

  It's the push pull again.

• 2:16:24Speaker 07

  It's a push pull again, you know, it's, you know, it's chest and back. It's, you know, whatever you want to think of. That's why I think if you're trying to increase dramatically drive up your serotonin levels at night and that sustains throughout the night when you're trying to get into REM sleep, you could be artificially fragmenting REM sleep. Now, I don't know the data. I don't think anyone's really got good data.

• 2:16:48Andrew D. Huberman?

  No, I haven't been able to find it.

• 2:16:51Speaker 07

  You know, if you were to say, Matt, two years' time, that's the data. Help me understand the potential mechanism or let's design some experiments. Where would you go first? I would say, let's look at the disruption of REM sleep, non REM sleep reciprocal regulation. Because, you know, you need serotonin to be, you know, up at one time, down at another.

• 2:17:11Andrew D. Huberman?

  So I, I agree with everything you said and I'm, I'm personally never taking tryptophan or serotonin again unless there's some clinical reason for that, that I would need to do that. I want to ask about some other pro sleep behaviors, but before I do that, let's talk about naps. I love naps. I come from a long history of nappers. My dad always took a nap in the afternoon. I take a 20 or 30 minute nap or I do a practice which I took the liberty of coining NSDR, non sleep deep rest, some sort of just passive laying or out there, feet up elevated. Sometimes people do you, or I'll do yoga nidra, I'll do hypnosis

• 2:17:53Andrew D. Huberman?

  or something of that sort. But 20 or 30 minutes of that has been very beneficial for me to get up from that nap or period of minimal wakefulness, we'll call it, and go about my day quite well and also fall asleep just fine. What are the data on naps? Do you nap? And what are your thoughts about keeping naps short, meaning 20 to 30 minutes versus getting out past 90 minutes, two hours? So for you personally, naps, yay, nay, or meh?

• 2:18:26Speaker 07

  I don't nap, um, and I've just never been a habitual napper.

• 2:18:32Andrew D. Huberman?

  Is that because you don't feel sleepy in the afternoon?

• 2:18:35Speaker 07

  Don't feel sleepy.

• 2:18:36Andrew D. Huberman?

  So you're just hardier than.

• 2:18:37Speaker 07

  I am, I wouldn't say hardier, I may be, um, less capable of falling asleep.

• 2:18:47Speaker 07

  No, no, I don't.

• 2:18:49Andrew D. Huberman?

  So you don't nap because you don't feel a need to nap?

• 2:18:51Speaker 07

  That's right. Yeah. Now, it's not that I am immune to what we call a postprandial dip in alertness. I definitely feel as though there can be this kind of afternoon, afternoon lull. Where, you know, I'm not quite as on as I was at 11 o'clock in the morning. And we know the physiology to that, which brings us back to whether we were designed to nap. So for naps, we've done lots of different studies and other colleagues have done these studies too. Naps can have some really great benefits. We found benefits for cardiovascular health, blood pressure, for example. We found benefits for levels of cortisol. We found benefits for learning and memory and also emotional regulation.

• 2:19:32Andrew D. Huberman?

  How long are the naps typically in those studies?

• 2:19:34Speaker 07

  Anywhere between 20 minutes to 90 minutes. Sometimes we like to use a 90 minute window. So that the participant can have a full cycle of sleep. And therefore they get both non-REM and REM sleep within that time period. Then when we wake them up, we usually wait a period of time to get them past what we call sleep inertia. Which is that kind of window of grogginess where you say to your better half, look, you know, darling, please don't speak to me for the first hour.

• 2:20:00Andrew D. Huberman?

  Don't anything right now.

• 2:20:01Speaker 07

  After the first hour of waking up, you know, I'm not just, I'm just not the best version of myself. So we wait for that time period and then we do some testing. And we've done some testing before and after, and we look at the change. And that's how we measure what was the benefit of naps. And the reason why we sometimes do 90 minutes, so that they get all of those stages of sleep. And then we correlate how much benefit did you get from the nap? And how much of that benefit was explained by what REM sleep you got, what deep sleep you got, what light sleep you got. So that's the only reason that we use that as an experimental tool. What we've also found is that naps of as little as seventeen minutes can have some quite potent effects on, for example, learning. None of this is novel.

• 2:20:45Speaker 07

  NASA pioneered this back in the nineteen nineties. And during the missions, they were experimenting with naps for their astronauts. And what they found was that naps of little as twenty-six minutes improved a mission performance by thirty-four percent and improved daytime alertness by fifty percent. And it birthed what was then called the NASA nap culture throughout all terrestrial NASA staff during that time period. So it's long been known that naps can have a benefit. Naps, however, can have a double-edged sword. There is a dark side to naps. And it comes back to our story of adenosine and sleep pressure.

• 2:21:27Speaker 07

  The longer we're awake, the more of that sleep pressure adenosine that we build up. But what I didn't tell you is that when we sleep, the brain gets the chance to essentially clear out that adenosine. And after about sixteen hours of wakefulness, and then after about eight hours of sleep, eight hours of sleep seems to be able to allow the brain to decrease its adenosine levels back to normal. And so naturally, we should start to wake up, which also aligns with your circadian rhythm, and those are two separate processes. But with about eight hours of good quality sleep, seven to nine hours for the average adult, we are free of all of that adenosine.

• 2:22:07Speaker 07

  We've evacuated it essentially out of the brain, and we wake up naturally feeling refreshed. The reason that naps can be potentially dangerous is that when you nap, you are essentially opening the valve on the pressure cooker of sleep pressure. And some of that sleepiness is lost by way of the nap. So for some people, and not all people, and you're a great example of this. Some people, however, if they are struggling with sleep at night and they nap during the day, it makes their sleep problems even worse. So for people with insomnia, we typically advise against napping. And the advice is if you can nap regularly and you don't struggle with sleep at night,

• 2:22:51Speaker 07

  then naps are just fine. But if you do struggle with sleep, stay away from naps. If you are going to nap, try to limit your naps. Try to cut them off a bit like sort of caffeine. Maybe, you know, eight to sort of 12 hours, maybe not that, you know, far off. Maybe sort of seven to six hours is a good rule of thumb. Try not to nap essentially late in the afternoon. And if you do take a nap and you want to maintain your, you don't want to have that grogginess hangover that can happen after a full night of sleep for the first hour. Try to limit it to about 20, 25 minutes. And that way you don't go down into the very deepest stages of sleep, which I, if I wrench you out of with an alarm, then you just kind of feel,

• 2:23:36Speaker 07

  you almost feel worse for the first hour after the nap.

• 2:23:39Andrew D. Huberman?

  I've definitely experienced that if I oversleep. Certainly if the sun goes down during my nap and I wake up and light, overall lighting conditions have changed. I find it very hard to jolt myself back into the evening and it can screw me up. So I try and keep those naps pretty brief. And I should say, um, I, I'm very happy to hear you mention individual differences and why some people might want to nap and other people might not want to nap. Uh, I have a colleague, Leechin Lo, he'll be familiar to many neurobiologists, but who's a absolutely spectacular scientist, um, member of the National Academy, Howard Hughes investigator, just a phenom and has a ton of energy. But years ago, I learned that he always takes a nap in the afternoon,

• 2:24:22Andrew D. Huberman?

  so much so that when he travels to give seminars at other universities, he will tell his post lunch, um, per host, whoever it is that he's supposed to meet with, may I have your office for 30 minutes of our, sometimes 30 minute discussion or 60 minute discussion because I like to take a nap. And he does that and then gives his, his talks are typically in the afternoon in academic culture. And he. describes the the effect of the nap for him, the short naps in the afternoon being so profound for his productivity. That's actually what inspired me to start feeling okay about my desire to nap.

• 2:24:57Speaker 07

  Yeah.

• 2:24:57Andrew D. Huberman?

  And so I think for me, that was great vindication for those that might feel guilty about wanting a nap. But I I take to heart your note about avoiding naps if you have trouble falling and staying asleep. Because I think that I have family members who also, if they nap, they're a wreck. They can't sleep.

• 2:25:14Speaker 07

  Yeah, I think it's just we've often been very pro sleep, we as the sort of the sleep community. So I think it's good to always point out these potential dark sides of of any aspect. But you're absolutely right. No one should feel guilty about getting the sleep that they need. And I think that's been one of the big problems in society. Society has stigmatized sleep with these labels of being slothful or lazy. And we're almost embarrassed, you know, to tell colleagues that we we take a nap. I think sleep is a right of human beings. And I therefore think that sleep is a civil right of all human beings. And no one should make you feel un-proud of getting the sleep that you need.

• 2:25:59Andrew D. Huberman?

  Well, I I love that. And it's an important point. I also feel that one of the best ways to beat your competition in any endeavor is to outlive them. So now that we know that sleep can enhance longevity and lack of sleep can shorten one's life. That's all the justification I need, anyway. Can somebody sleep too much? Is it possible to get too much sleep?

• 2:26:26Speaker 07

  It's a very good question. And there are probably two things to say about it. There is a condition that we call hypersomnia. But that's a mixture of things. It's where people have either a very high sleep need. Or they are very sleepy during the day and they're typically falling asleep. And these can happen in a variety of different clinical contexts. One of the places where we've often seen hypersomnia believed to manifest is in depression.

• 2:26:57Speaker 07

  But if you look at some of those studies, it turns out it looks more as though those people are simply reporting being in bed longer, but not necessarily sleeping longer. And that fits very well with one of the profiles that we know of depression, which is anhedonia. You don't get pleasure from normally pleasurable things. So you just don't want to go out into the world. You don't want to interact because you're depressed. So what do you do? You just stay in bed.

• 2:27:23Andrew D. Huberman?

  Blind clothes, watching TV.

• 2:27:25Speaker 07

  Right. And that just looks as though, you know, when people say, what time did you go to bed? And what time did you get out of bed? The mistake made in that question is, okay, that's how much time they're sleeping, when you should have said, what time did you fall asleep? And what time did you wake up? And the answer could be very different. So that's hypersomnia from a clinical context. Can you sleep too much, though? One of the data points that argues, yes, that's possible, is when we look at all-cause mortality. Certainly, what you find is that using the sweet spot of seven to nine hours, when you start to drop below seven hours, there is a relationship which suggests that the shorter your sleep, the shorter your life. Short sleep in that regard predicts all-cause mortality. But

• 2:28:10Speaker 07

  it's again, not a linear relationship like the one that we've seen with REM sleep. Once you get past nine hours, the mortality curve stops going down. And then, once you get further, ten, eleven hours, it hooks back up again. It's almost like a J shape, tilted over a little bit and reversed. So there's this strange hook. What's going on here? Right now, sleep science has at least two non mutually exclusive explanations for this. The first is that if you look at some of those populations, the idea is that the whatever was causing them illness and took their lives was just too much for sleep to deal with. However, we know that when we get sick, one of the things that we do immediately, and

• 2:28:53Speaker 07

  there's a whole mechanism, an inflammatory mechanism, cytokine mediated, when we get sick, we want to sleep more. We just want to pile up in bed and, you know, sleep it, sleep it off. So the argument there is that it's not that sleep was killing people prematurely. It was that these people were calling on this, the help of sleep. They were calling on this thing called the Swiss Army Knife of Health, that is, sleep. But whatever it is that they were facing was just too powerful for sleep to overcome. So it artificially looks as though more sleep leads to a higher risk of death. When sleep was actually responding to the mortality risk and it lost the battle. That's one argument.

• 2:29:36Speaker 07

  The second is that we know that sleep quality and poor sleep efficiency is a very strong predictor of all cause mortality. And when you look at people who often report sleeping long amounts, 10 or 11 hours, they typically report having very poor quality sleep. So because their quality of sleep is poor, they just try to sleep longer to try and get some of that back. So again, here now, it's poor quality sleep masking as too much sleep, leading to this artificial huck, which looks like mortality. That's a second explanation. A third, which is more of a Gedanken, which is just a kind of like a thought experiment.

• 2:30:20Speaker 07

  And I'm of this mentality, I don't know how many other people share this. I actually think there could be a thing as too much sleep. Physiologically, I think it's possible. But the reason I think that is because it's no different than food, water, or oxygen. Can you overeat? Yes, you can. Can you undereat? Of course.

• 2:30:42Andrew D. Huberman?

  Or light, light in the early part of the day, throughout the day, wonderful. Light late in the day, at night, detrimental.

• 2:30:47Speaker 07

  Bidirectional, you know, for water, can you overhydrate? Hypn- uh, nutriment, it can lead, you know, it happened in the 1990s and 2000 with the ecstasy craze, where governments were saying, you're dehydrating, you're dancing all night, please drink water. And they drank too much water. Their blood electrolytes went, you know, all over the place and they were having cardiac arrests or stroke.

• 2:31:09Andrew D. Huberman?

  Yeah, people were dying.

• 2:31:10Speaker 07

  And they were dying because of excessive hydration. Can you get too much oxygen, hyperoxemia? And it can cause free radical damage, which can be profoundly harmful and kill brain cells. Can you sleep too much, you know, which is the fifth element of the life equation, you know, alongside, you know, food, water, oxygen, um, you know, so fourth, I should say, can't even count. Clearly I'm sleeping well. Um, yes, I think there could be that possibility. Are most people in danger of getting too much sleep? Oh, contraire, if you look at the data.

• 2:31:48Andrew D. Huberman?

  Right.

• 2:31:49Speaker 07

  So, but I, I don't dismiss that idea. I think it's, it's possible.

• 2:31:53Andrew D. Huberman?

  That's, that's a very thorough and very nuanced and you have very clear answer. So I, I, it's so interesting to think that a lot of the, the, the data that out there that talking about being in bed too long, that it's just trying to compensate for the actual fragmentation of sleep. So the, what I'm coming away with is that there are many paths to this and uh, both positive and things to avoid, but the idea is to get most nights a similar amount, probably seven to nine hours, somewhere in there of high quality sleep, that this notion of sleep quality is going to become, uh, I would hope, uh, a phrase that more people think about and learn about and cultivate

• 2:32:33Andrew D. Huberman?

  as a practice. Uh, I want to ask about a, a set of behaviors that I'm at least, I'm aware of at least one company is starting to track in their sleep monitoring device and that's, um, orgasm. And sex, orgasm and masturbation, topics that are, uh, you know, are somewhat, um, sensitive. But, uh, from the perspective of biology, right? Uh, none of us would be here were it not for a sperm meets egg in some fashion, either in a dish or, or in vivo. Um, but what, what are the data as, as you know them to be, or maybe your lab is even doing this kind of, um, uh, work

• 2:33:14Andrew D. Huberman?

  and exploration about the role that sex, orgasm, masturbation play in getting to sleep and staying asleep and sleep quality. Certainly those behaviors and those physiological events have been part of our evolutionary history.

• 2:33:29Speaker 07

  Right.

• 2:33:29Andrew D. Huberman?

  Um, what's the story there? Uh, what can we say about this in, in terms of, um, science and, and dare I say, practice?

• 2:33:38Speaker 07

  Yeah, I mean, it's almost that caricature of, you know, in the movies where, you know, a couple makes love and then all of a sudden you just sort of hear snoring or, you know, it happens with the idea that it's somewhat somnogenic, that it's sleep promoting.

• 2:33:54Andrew D. Huberman?

  Well, the post-orgasmic increase in prolactin

• 2:33:56Speaker 07

  Well, that's very interesting.

• 2:33:59Andrew D. Huberman?

  Is thought to be a naturally occurring sedative that presumably has a function in.

• 2:34:04Speaker 07

  And oxytocin has that also that benefit where you see, you know, a dissipation of the fight or flight branch of the nervous system, which has to happen for you to fall asleep. That's why we often see, you know, here at the sleep center, we'll see a phenomenon called wired and tired, where people say, look, I am so desperately tired. I just, I'm so, so tired, but I can't fall asleep because I'm too wired. So your sleep drive, you're desperately tired, it's there. But because you're wired, because you've got too much sympathetic activation, too much cortisol as well, you can't fall asleep. It's a, it's an impressive roadblock to anything like good sleep. And it's one of the principal

• 2:34:47Speaker 07

  mechanisms that we now believe stress and physiological activation, that is the underlying cause of many forms of insomnia. But coming back to sex, the data is actually quite compelling that both either subjectively assessed sleep quality or objective amount of sleep, sex that has resulted in orgasm, and I think it's that latter part that typically needs to happen.

• 2:35:15Andrew D. Huberman?

  I would imagine so.

• 2:35:16Speaker 07

  That, you know, so between two mutually exclusive individuals where both are, you know, beneficial in terms of receiving an orgasm.

• 2:35:27Andrew D. Huberman?

  Yeah, I always say, any discussion about sex, we are referring to consensual, age-appropriate.

• 2:35:35Andrew D. Huberman?

  Species appropriate, context appropriate.

• 2:35:37Speaker 07

  Wow, I would never have even gone to the species appropriate.

• 2:35:39Andrew D. Huberman?

  I put species in there because it's the internet and people will come up with all sorts of ideas. So I, I think the age appropriate, I think age appropriate, consensual, context appropriate and species appropriate covers all the bases, but if I missed any, put them in the comment section and we'll be sure to take note.

• 2:35:53Speaker 07

  Yeah, no, I think that's, uh, that's really well said, um, and important to say. So the data is the, when you look at couples who have orgasm, we've also however, found benefits of masturbation and it's not frequently spoken about, but what it, if you do some surveys, it turns out that people will often use masturbation as a sleep tool if they're struggling with sleep. And I know this sort of sounds almost like a strange conversation or it's a taboo conversation, but I, I think we just need to be very open about all of this.

• 2:36:27Andrew D. Huberman?

  I started off in science, um, one of the things I worked on, uh, early in my career, not the very first topic was, uh, the topic of early influences of hormones, estrogen and testosterone on sexual development of the brain and body. And when you are weaned in a laboratory like that, regardless of what era, you look at sex and its behaviors and its hormones and its physiologies as a scientist. And so I think that's, to be clear, what we're doing here, we're exploring these, um, these behaviors from that, from that perspective. I mean, one thing is for certain, everyone is here because a sperm and an egg, either in a dish or in vivo, as we said before, and, um, at least in 2021, there's, there's no way around that fact.

• 2:37:11Speaker 07

  Yeah.

• 2:37:12Andrew D. Huberman?

  And what preceded that is typically this act we call sex and sometimes, hopefully, uh, I like to think, uh, orgasm is associated with that sexual activity. Masturbation as one dimension of that is something that I think it can and should be discussed if in fact there are data that relate it to sleep.

• 2:37:30Speaker 07

  Yeah, and both of those roots seem to lead to, um, a sleep benefit. Now, I'm not saying that it's all about the orgasm. I think as we spoke about with oxytocin, there is some degree of per bonding that if you have a partner and you experience, you know, an intimate, loving, you know, relationship. That involves that, then you can have hormonal benefits that are sleep promoting that may not necessarily be seen if you're just engaging, you know, in the solo singular act of masturbation. So what we certainly know, and I, I am not someone to take any advice on when it comes to anything relationship wise or sex wise.

• 2:38:13Andrew D. Huberman?

  That's a different episode of the podcast.

• 2:38:15Speaker 07

  Certainly, and that's not a podcast series that I'm going to be releasing anytime soon. It's going to be mostly about sleep, although I will touch on, I'll release a podcast on sleep and sex. But that's the data that we have so far. We also know that it works both ways, though, and it's commonly the same way with sleep, you know, sleep and exercise, sleep and diet. How you eat can affect how you sleep, how you sleep can affect how you eat. Same with exercise. And it turns out it's the same way with sexual behavior too. So here we're talking about whether sex can help with sleep. Can sleep help with your relationship and sex? And the answer is yes, it can. Firstly, we know, and we've

• 2:38:59Speaker 07

  spoken a little bit about this, that the reproductive hormones are under profound sleep regulation.

• 2:39:04Andrew D. Huberman?

  Both estrogen and testosterone.

• 2:39:05Speaker 07

  Estrogen, testosterone.

• 2:39:06Andrew D. Huberman?

  Because we hear so often about testosterone. But women who, or I should say, anyone who's interested in having higher levels of estrogen or, or normal, healthy levels of estrogen, I presume the data show for estrogen, what the data also show similarly for testosterone, which is if you get too little or poor quality of sleep, the both sex steroid hormones, as they're referred to, testosterone and estrogen, which are present in both males and females and every variation thereof, are going to be diminished below normal, healthy levels.

• 2:39:36Speaker 07

  Yep, estrogen, testosterone, FSH in women, a key hormone in the regulation for, key for conception, of course. All of these sex hormones seem to become significantly disrupted when sleep becomes of short quantity or poor quality. We also know that in women, sleep disruption can usually lead to menstrual cycle disruption. We know this particularly from evidence in shift working women where they are nighttime shift workers, they struggle with sleep during the day. Often menstruation is disrupted or even becomes impaired.

• 2:40:17Speaker 07

  But we also know it works this way, not just for sex hormones, but for sex itself. For example, we found that for every one hour of sleep, extra sleep that a woman gets, her interest in becoming sexually intimate with her partner increases by 14%, which is, you know, a non-trivial amount. And then the final part of, I think, this equation when it comes to sleep and sex is your your relationship itself. And there's some great work here from UC Berkeley by Professor Serena Chen. And what she found was that restless nights mean for far more brutal fights in your relationship.

• 2:41:01Speaker 07

  And they did this in a number of different elegant ways and vice versa as well.

• 2:41:05Andrew D. Huberman?

  I mean, not that I've ever had conflict in relationships.

• 2:41:07Speaker 07

  Me, like, you know, I just, this is just data I've read. I've never experienced that at all. So, and they found reliably that sleep would predict higher likelihood of relationship conflict. Secondly, if you got into that conflict, the chances of you resolving it were significantly lower when the parties had not been sleeping well. Part of the reason is because when you are not well-slept, your empathy goes down. So you're not, you're taking more of an abrasive stance with your partner rather than a more agreeable stance with your partner.

• 2:41:46Speaker 07

  So at almost every dimension of a human-loving relationship, sleep can have a dramatic impact.

• 2:41:54Andrew D. Huberman?

  I think these are really important things to underscore. One of the most common questions I get, because there seems to be a community of people on the internet that are obsessed with this, I don't know who they are, because it's all, all this internet stuff is shouting into a tunnel and getting comments back and written form. It's a very bizarre conversation, so to speak, is whether or not sexual behavior itself lowers or increases testosterone. And I went into the data, which spans many decades, actually, both animal studies and human studies. And it seems, just to underscore this, as long as we're talking about this subject, that it does seem that sexual activity, sex between two people, does seem to increase testosterone in both.

• 2:42:44Andrew D. Huberman?

  There is this question about orgasm or no orgasm, ejaculation, no ejaculation. And, and indeed, there do seem to be some effects of, of, um, of restricting ejaculation in males as a form of further increasing testosterone. So sex without ejaculation, further increasing testosterone. But the data are not clean.

• 2:43:03Speaker 07

  Okay.

• 2:43:04Andrew D. Huberman?

  Um, presumably because organizing these sorts of studies and getting truth in, in self-reporting is probably hard to get from, from subjects. But, um, but it, everything sort of points in the direction that, provided that the relationship is a healthy one, it's, it's consensual, it's age-appropriate, context-appropriate, species-appropriate, that sex between two individuals does seem to increase the sex steroid hormones, testosterone and estrogen toward healthy ranges. And what I'm hearing now, the sort of gestalt of, of the discussion we just had, is that that too can promote sleepiness, restful states and quality sleep. And, um, I think this is an important conversation that just hasn't been, been held enough. I

• 2:43:46Andrew D. Huberman?

  mean, sooner or later, um, both in the US and elsewhere, we're going to have to acknowledge that we are biological organisms of some sort, and that we have choice in life about all these things, um, from supplementation to sex or no sex, et cetera. But that they have profound effects on our core biology. I mean, it's fascinating to me that the areas of the hypothalamus, the pre-optic area, the super-optic areas, those areas, which the names might not mean anything to anybody besides, uh, Matt and I sitting here, but those areas sit cheek to jowl with each other in the hypothalamus and control sleep and sex.

• 2:44:21Speaker 07

  Yeah.

• 2:44:22Andrew D. Huberman?

  The trigger of orgasm, the appetite for food, the appetite for water, for electrolytes. I mean, the hypothalamus is kind of a, um, a festival of, of neurons with different booths for different, um, primitive behaviors.

• 2:44:37Speaker 07

  Such a small, small structure in the brain, but it's the orchestrator of a vast number of our behaviors disproportionate in terms of its size versus effect.

• 2:44:45Andrew D. Huberman?

  Yeah. I don't think you can go to this hypothalamic festival without, uh, at least seeing all the booths, whether or not you decide to visit them or not.

• 2:44:52Speaker 07

  Oh, I love that. Master analogy.

• 2:44:54Andrew D. Huberman?

  So, um, so I'm glad that we've approached that conversation and I hope people will, um, will think that we've approached it with the appropriate level of sensitivity. It's, it's an important one that we're going to hear more about one way or the other. People are certainly thinking about this, if not, um, engaging in, in these sorts of behaviors or avoiding them. Um, so the more we can understand about the biology, the better.

• 2:45:15Speaker 07

  I'll say.

• 2:45:17Andrew D. Huberman?

  And so thank you for bringing that topic up because for the record, Matt, uh, tabled it for discussion.

• 2:45:23Speaker 07

  I said, we were just like chatting outside and I think we said something about, yeah, sort of section. And I said, yeah, we can go there. This is actually interesting data.

• 2:45:30Andrew D. Huberman?

  Absolutely. Um, I want to touch on just two remaining topics. One is, are there any unconventional sleep tips or things about sleep that, that we've overlooked? If, if we've covered everything, great, but, um, you know, we're here to keep the room cool. We hear, uh, because of this temperature phenomenon, the light aspects, the considerations about alcohol, CBD, marijuana, um, cognitive behavioral tart cherry fruit, kiwis, um, perhaps, perhaps.

• 2:46:02Speaker 07

  Please don't put me on the hook for tart cherries and kiwi. I was just offering what I know about the data.

• 2:46:07Andrew D. Huberman?

  And these are considerations and, and whether or not people, uh, batch these things. I, I won't even list them off now because there are too many jokes that one, one could make. Um.

• 2:46:16Speaker 07

  And I have no affiliation with any of these products or companies.

• 2:46:19Andrew D. Huberman?

  Well, I'm, I'm going to take out stock in a kiwi company. No, I'm just kidding. Um, but the question I have is about any unconventional or lesser known things, or maybe you do things or you think about things just in a purely, uh, exploratory way as a scientist of, you know, the, the what if, uh, kind of things that, you know, what if it turns out that, and I hear I just, I've got a blank there for you to fill in.

• 2:46:46Speaker 07

  I think, you know, beyond the standard, you know, fur that I've dished out plenty of times of sleep hygiene of, you know, regularity, temperature, darkness, um, alcohol, caffeine, and we've, we've spoken about all of those. What are some more unconventional tips, I guess?

• 2:47:05Speaker 07

  The first one, which is unconventional along the lines of naps. If you've had a bad night of sleep, let's say that you're starting to emerge with insomnia and you've had a bad night of sleep. The advice, and I learned this from my wonderful colleague, Michael Perles, do nothing. What I mean by that is, don't wake up any later, don't sleep in the following day to try and make up for it, don't nap during the day, don't consume extra caffeine to wake you up, to try to get you through the day, and don't go to bed any earlier to think that you're going to compensate. And I can explain all of those things, but if you wake up later, you're not going to

• 2:47:46Speaker 07

  be sleepy until late of the evening, so you're going to go to bed at your normal time and you won't be sleeping, you'll think, well, I just came off a bad night of sleep and now I still, I can't even get to sleep and it's my normal time. It's because you slept in later than you would otherwise, and you reduce the window of adenosine accumulation before your normal bedtime. So, don't go, don't wake up any later, don't use more caffeine for the reasons that are obvious, because that's only going to crank you and keep you awake the following night or decrease the probability of a good following night of recovery sleep. Third, I mentioned, don't take naps, because once again, that will just take, you know,

• 2:48:27Speaker 07

  naps particularly later in the afternoon, I almost liken them to snacking before a main meal, it just takes your appetite off the edge of that main meal of sleep, so don't do it. And then finally, don't go to bed any earlier, resist and resist and go to bed at your normal time. What I want to try and do is prevent you from thinking, well, I had such a bad night last night and I normally go to bed at 10:30, I'm just going to get into bed at nine o'clock because last night was just so bad. But that's not your natural bedtime and it's not aligned with your natural chronotype, because presumably you kind of know something about that, or morning type, evening type, you're trying to sleep in harmony, which is usually how you get best quality sleep.

• 2:49:08Speaker 07

  But you go to bed at nine and my body is not ready to sleep at nine o'clock. But I'm worried because I had a bad night of sleep last night. So I get into bed and now I'm tossing and turning for the first hour and a half because it's not my natural sleep window, but I just thought it was a good idea. And if I didn't know anything about sleep, I would think all of these same things too. So I'm not finger wagging. But after, if I have a bad night of sleep and I am not immune, just because I know a little bit about sleep, doesn't mean I don't have my bad nights. I do, doesn't mean I haven't had bouts of insomnia in my life. I have. But after a bad night of sleep, I do nothing. I don't do any of those four things.

• 2:49:50Speaker 07

  I think the second tip I would offer in terms of unconventional is have a wind down routine. Many of us think of sleep as if it's like a light switch that we just jump into bed and when we turn the light out, sleep should arrive in that same way. Just the binary, you know, it's on or it's off. Sleep is a physiological process. It's much more like landing a plane. It takes time to gradually descend down onto the terra firma of what we call good, solid sleep at night. Find out whatever works for you and it could be light stretching. I usually meditate for about 10 or 15 minutes before bed. Some people like reading. Try not to watch television in bed.

• 2:50:35Speaker 07

  That's usually advised against.

• 2:50:36Andrew D. Huberman?

  Too much light to your eyes.

• 2:50:37Speaker 07

  Too much light, too activating. You know, you can listen to a relaxing podcast, although we can speak about technology in the bedroom too. But have some kind of a wind down routine. It's, you know, it's almost like, you know, you wouldn't race into your garage and come to a screeching halt from 60 miles an hour. You typically downshift your gears and you slow down as you come into the garage. There's the same thing with, with sleep too. So that's the second thing. Have some kind of a wind down routine. Find what works for you. Maybe it's taking a hot bath or a warm shower and then stick to it. Just, we do this with kids all the time. We find out what their bedroom, sorry, their bedtime regiment is.

• 2:51:20Speaker 07

  And then we just stick to it faithfully because we humans are the same way too. The third thing is a myth, don't count sheep. There was a study done here at UC Berkeley. I didn't do this today. I wish I did. It was by my colleague, Professor Alison Harvey. And they found that counting sheep actually made it harder to fall asleep. It made matters worse. As a counter, sorry, counter measure to that, what they did find was that taking yourself on some kind of a mental walk. So think about a nice walk that you take in nature, or a walk on the beach, or even a walk around an urban environment. And visualizing that, that seemed to be beneficial.

• 2:52:00Speaker 07

  The other thing about sort of that idea of shifting focus away from your mind itself, get your mind off itself is a good piece of advice. Catharsis, you can try to write down all of the concerns that you have. And do this not right before bed, but usually an hour or two before bed. Some people call it a worry journal. And to me, it's a little bit like closing down all of the emotional tabs on my browser. Because if I shut the computer down and all of those tabs are still open, I'm going to come back in the morning and the computer's red hot, the fan's going because it didn't go to sleep, because it couldn't, because there were too many tabs active and open.

• 2:52:45Speaker 07

  I think it's the same way with sleep as well. So try to think about doing that. So just vomit out all of your concerns on the page.

• 2:52:52Andrew D. Huberman?

  I like that, because my 3am waking is often associated with me writing down the list of things that I forgot to do, that I need to do.

• 2:52:58Speaker 07

  Yeah.

• 2:52:58Andrew D. Huberman?

  And in, in, once I eventually wake up from the later night, uh, second half of the night's sleep, that stuff seems much more tractable and reasonable, but uh, it sure would be great to get that stuff out of the way before sleep.

• 2:53:10Speaker 07

  Well, there's also something that I don't think people have spoken about a lot, and I'd like to research it, which is.

• 2:53:19Speaker 07

  Difficulty and anxiety at night in the dark is not the same difficulty and anxiety in the light of day. And when we have those thoughts at night, it comes with a magnitude of rumination and catastrophization that is disproportionate to that which you would describe when you are awake. And I don't know what's going on about the brain and thought and emotion at the time. I've got a bunch of theories as to why. And that's why I like the idea of closing up, zipping up all of those different components, just

• 2:54:01Speaker 07

  get them out on the page. And it feel, and I at first thought, this just sounds like Hui, it sounds very Berkeley, it's kind of come by our, we all hold hands and, you know, walk home at the end of the day. But then the data started coming out, really good studies from good people, and they found that keeping one of those generals decreased the time it takes you to fall asleep by 50%, five zero. You know, it's well on par with any pharmaceutical agent.

• 2:54:27Andrew D. Huberman?

  Oh, absolutely. Yeah, I'm convinced that, well, I've long thought that the worries and concerns and ideas I have at 3, 4 a.m., I've learned to not place any stock in them.

• 2:54:38Speaker 07

  Yeah.

• 2:54:38Andrew D. Huberman?

  Because something, I'm glad that you might decide to eventually look at this in your laboratory, because I feel like something has melted away or altered. I suspect it's in the, the regulation of the autonomic nervous system, that it makes sense why a concern at 3, 4 a.m. ought to evoke more of a panic sense than a concern sense. And certainly, that's my experience, although not, I'm fortunate to not suffer from full-blown panic attacks, but everything seems worse at 3, 4 a.m.

• 2:55:08Speaker 07

  Yeah.

• 2:55:08Andrew D. Huberman?

  Provided you're awake.

• 2:55:09Speaker 07

  And we need to sort of look into that, because, you know, if you look at suicide rates. Around the 24 hour clock face disproportionately higher rates in those middle sort of night hours. So now, now I don't know if that's causative or not, but something, you know, it could just be that that's the time when we're mostly lonely and we're by ourselves. And that's the reason. So it's got nothing to do with sleep or the nighttime. I don't know. So that's the third thing. I think the fourth sort of little tip I would give that's unconventional is remove all clock faces from your bedroom.

• 2:55:43Andrew D. Huberman?

  Including your phone.

• 2:55:44Speaker 07

  Including your phone and resist checking it. Now I know, and I can speak about the phone too. That genie of technology is out the bottle and it's not going back in anytime soon. So we've got to think as scientists and sleep scientists. You know, as to what we do with, you know, phones in the bedroom.

• 2:56:02Andrew D. Huberman?

  Years ago, I was a counselor at a summer camp. I worked with at-risk kids and the, um, there was a phrase that comes to mind here. It's be a channel, not a dam. Because when you try and dam certain kinds of behavior, um, physically dam certain kinds of behavior, not morally dam. That too, uh, it just creeps over the edge and you get, and you get a waterfall. So it has to be channeled. The phone and devices have to be worked with and negotiated, not eliminated.

• 2:56:30Speaker 07

  And, you know, think about those mindfully too, but clock faces, remove all of those because if you are having, you know, a tough night. Knowing that it's three 22 in the morning or it's four 48 in the morning does not help you in the slightest. And it's only going to make matters worse than better. So try to remove all clock faces. And I think that's one of those other tips that some people have found helpful, but those would be sort of some slightly unconventional. I guess more than your stock fare of here are the five tips for sleep hygiene tonight. So.

• 2:57:06Andrew D. Huberman?

  Those are terrific sleep tips and several of which, if not all of which, I'm going to incorporate. Matt, this has been an amazing deep dive on sleep and its positive and negative regulators.

• 2:57:18Speaker 07

  I hope it hasn't been too long and I don't.

• 2:57:20Andrew D. Huberman?

  No, this has been great.

• 2:57:21Speaker 07

  Please cut it down, shorten it to, you know, the five minutes of meaningful stuff that I offer.

• 2:57:26Andrew D. Huberman?

  Absolutely not. It is chock a block full of valuable takeaways. It's been tremendously fun for me to dissect out this incredible aspect of our lives that we call sleep with a fellow scientist and a fellow public educator. I want to say several things. First of all, we should say where people can find you, although it shouldn't be that difficult these days. You're very present on the internet.

• 2:57:54Andrew D. Huberman?

  For better or for worse. I think it's wonderful that you're out there. Look, it's a public health service that you're doing. No one requires you or any other scientist to get out and share this information. My sense of you, knowing you a bit, and from following your work very closely, both your scientific work in detail and your public facing educational work, is that you very much want the best for people. And it's an interesting thing as a scientist or a clinician to know that the, that certain answers exist, that we don't have all the answers, but that there is a better path, there are better ways, and people can benefit in a myriad of ways.

• 2:58:31Andrew D. Huberman?

  So for that, because I know that to be very genuine in you, you want the best for people and you're offering tremendous advice and considerations and people can take it or leave it. That's the way I view it. I also want to thank you for taking the time out of your day to, to sit with me here and have this discussion.

• 2:58:50Speaker 07

  Not at all. It's a privilege. It's a delight. You know, you and I, I think, were like kind in lots of ways and. I take you as a shining example of how you can effectively connect with the public. And I know that we've had our conversations before we ever sat down sort of together about, you know, how to think about communicating with the public and the pros and cons of that. And I've just loved your opinions. I've been drinking it all in. And then I think the third thing I'd like to say is, thank you for being such an incredible sleep ambassador. The series that you've released on sleep, the way that

• 2:59:29Speaker 07

  you speak about sleep, the way that you moderate and have championed sleep, it is remarkable. So, thank you for just being, you know, a brother in arms in that way.

• 2:59:41Andrew D. Huberman?

  Well, we are, and thanks for those words. Ninety-nine percent of what I discussed there was the work of you and your colleagues in the sleep field. So, proper acknowledgement, but thank you. Where can people learn more about what you're doing currently and what's coming next? You're on Twitter.

• 2:59:57Speaker 07

  I am on Twitter. I typically tweet.

• 3:00:01Andrew D. Huberman?

  As the Sleep Diplomat.

• 3:00:03Speaker 07

  So, it's no, it's just Sleep Diplomat.

• 3:00:05Andrew D. Huberman?

  Sleep Diplomat.

• 3:00:06Speaker 07

  Sleep Diplomat on Twitter, sleepdiplomat.com website. If you want to learn more about the science that we do here, it's humansleepscience.com. It's the Center for Human Sleep Science. You can pick up a copy of the book if you want. It's called Why We Sleep. If you're curious about sleep, that's one path to take and it's.

• 3:00:30Andrew D. Huberman?

  Is there another book someday in the in the future?

• 3:00:33Speaker 07

  I think there may be. Yeah.

• 3:00:35Andrew D. Huberman?

  Right. Many, many millions of people will be very happy to hear that.

• 3:00:39Speaker 07

  I think it's starting to take hold. And then, as we discussed, I am more than kicking around the idea of a short form podcast rather than a long form. Not long form because I don't have the mental capacity or the interviewing, just capability that someone like you has. So, it will probably just be monologue short form. So, if there is some interest, I'll probably do that as well. So, those are the ways that. People can find me, but overall, if you're interested in sleep, just listen to Andrew. That's the best thing I can tell.

• 3:01:15Andrew D. Huberman?

  All right. Well, now, now we're batting back and forth, the, the, the vector of action, so to speak, but um, I do hope you'll start a podcast, however brief or lengthy these episodes uh turn out to be, because I do believe that's a great venue to get information out into the world. And um, we don't just uh want to hear more from Matt Walker. I speak for many people. Um, we need to. The work you're doing is both um influential, but more importantly, it is important work. It, it has the impact that's needed, especially in this day and age where science and medicine, public health, and the, the issues of the world, et cetera, are really converging. So I know I speak on behalf of a tremendous number of people. And I just say, thank you for doing the work you do and for being you.

• 3:02:01Andrew D. Huberman?

  And thanks for being a, a good friend.

• 3:02:02Speaker 07

  Likewise, too. Um, and by the way, I, I just going to note that it was nice that the two of us both got the um Johnny Cash uh memo about how to dress today. Uh, it seems as though we're both kind of uh, we got that same memo, which will, will mean nothing to people who are listening, but if you're watching the video, you'll probably see what I mean. Uh, Andrew, thank you for taking this time. Thank you so much.

• 3:02:25Andrew D. Huberman?

  So much, Matt. Thank you for joining me for my discussion with Dr. Matt Walker. Please also check out his podcast, The Matt Walker Podcast. A link to that podcast can be found in the show notes. If you're enjoying this podcast, please subscribe to us on YouTube. On YouTube, you can also leave us comments and suggestions for future episodes and guests in the comments section. As well, please subscribe to us on Apple and on Spotify. And at Apple, you can leave us up to a five star review. Please also check out our sponsors mentioned at the beginning of this episode. Links to those sponsors can be found in the show notes.

• 3:03:00Speaker 01

  Mr. President, my company told me of the explosion on our rig on October 2nd. Causing massive water displacement and triggering a tsunami. They all keep the blame on me. Tom Cruise is.

• 3:03:10Speaker 02

  Digger got us into this mess, and Digger's gonna dig us up. From the director of Birdman and the Revenant.

• 3:03:16Speaker 03

  What would happen if I stopped drilling? You're stalled, you freeze to death, that's what.

• 3:03:21Speaker 02

  With great power comes great deniability.

• 3:03:24Speaker 03

  I'm not the first nanny.

• 3:03:25Speaker 02

  Digger. See the trailer online. Only in theaters October 2nd. Rated R. Under 17 ninety without parent.

• 3:03:30Andrew D. Huberman?

  And last, but certainly not least, thank you for your interest in science.