Running: Will It Wreck Your Body?

Lots of us love — or love to hate — running. And we do it because it’s supposed to be healthy, right?! But then we hear tons of stories about runners getting hurt — sometimes so badly that they have to hang up their sneakers. And there are people on social media going even further, claiming it’s one of the worst things we can do for our bodies. So IS running secretly bad for us? And could too much of it actually bring you closer to a heart attack? We’ll explore the science on all of that, and we’ll also dig into runner’s high: What is going on in the brain to cause this feeling? With help from Dr. Rasmus Østergaard Nielsen, Professor Duck-Chul Lee, and Dr. Michael Siebers, we look at the science to find out if running is the key to a healthy life or if there are peer-reviewed reasons to be a hater. Find our transcript here: https://tinyurl.com/sciencevsrunning In this episode, we cover: (01:48) What’s the deal with running injuries? (10:51) How to get hurt less (15:03) The secret to a longer life (19:34) What is the runner’s high? (28:58) How to get runner’s high This episode was produced by Ekedi Fausther-Keeys with help from Blythe Terrell, Michelle Dang, Rose Rimler, Meryl Horn and Wendy Zukerman. We’re edited by Blythe Terrell. Wendy Zukerman is our executive producer. Fact checking by Taylor White. Mix and sound design by Bobby Lord. Music written by Bumi Hidaka, Peter Leonard, Emma Munger and Bobby Lord. Thanks to the researchers we got in touch with for this episode, including Dr. Anita Eberl, Dr. Johannes Fuss, Professor Robert Otto, Dr. Hirofumi Tanaka, Dr. Peter Kokkinos, Dr. Marilyn Moffat, and Director Brian Farr. A big thanks to Joseph Lavelle Wilson and the Zukerman family. Science Vs is a Spotify Studios Original. Listen for free on Spotify or wherever you get your podcasts. Follow us and tap the bell for episode notifications. Learn more about your ad choices. Visit podcastchoices.com/adchoices

• 0:00Speaker 00

  Hi, I'm Akedi Foster Keys, filling in for Wendy, and you're listening to Science Versus,

• 0:07Speaker 00

  the show that pits facts against 5Ks. Today on the show, running.

• 0:17Speaker 00

  More than 28 million people go running every week in the US, according to one survey.

• 0:23Speaker 00

  And the reason why we do this is presumably because it's good for us, right? And not only that, but we hear running can give you this sort of amazing feeling.

• 0:32Speaker 01

  It's time to get high, runner's high, that is.

• 0:35Speaker 02

  I had ran two miles straight and I experienced a runner's high for the very first time. It was so freaking cool. It was like full adrenaline.

• 0:42Speaker 00

  So a lot of us are excited about the benefits of running. But then we also might have this nagging voice in our ear that's kind of just like, you're gonna get hurt.

• 0:53Speaker 03

  Everyone I know that starts to get into running, their body slowly starts to fall apart.

• 0:58Speaker 04

  Don't run, period. I'm so tired of saying it. Your knees go, your ankles go, your hip goes.

• 1:05Speaker 02

  Running is terrible for you, and anybody who runs a marathon, I think, needs mental health help.

• 1:10Speaker 00

  And so today, we're running down the science here. We're gonna figure out what actually happens to our bodies when we run, what's going on with our muscles and our joints. And then we're also gonna look into runner's high and figure out like, what's happening in our brains when this happens?

• 1:27Speaker 00

  Because when it comes to running, there's a lot of...

• 1:30Speaker 03

  Their body slowly starts to fall apart.

• 1:33Speaker 00

  And then there's science.

• 1:37Speaker 00

  That's coming up after the break.

• 1:46Speaker 05

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• 2:25Speaker 00

  Welcome back. I'm a Keddie Foster Keys. And today, we're looking at running and what it's doing to our bodies. With me today is senior producer Merrill Horn. Hey Merrill.

• 2:36Speaker 02

  Hey Keddie.

• 2:37Speaker 00

  So, are you a runner?

• 2:39Speaker 02

  I am a runner. Like, I don't run as much as I used to, but I love running. It's like my little escape, you know? I love it when I'm listening to the music and getting into the rhythm.

• 2:50Speaker 00

  I actually publicly hate running, but secretly kind of love it.

• 2:55Speaker 00

  I don't do it as much, though, because I got hurt.

• 2:57Speaker 02

  Yeah. I mean, I'm also scared right now to really get back into it, since my husband got super injured from running. Like, he wasn't doing anything that crazy, but he ended up getting a stress fracture and literally, like, just couldn't walk one day because of it and ended up being on crutches for, like, two months.

• 3:20Speaker 00

  Oh my god.

• 3:22Speaker 02

  Which I just didn't even realize could happen, so that really freaked me out.

• 3:26Speaker 00

  Jeez. So, that's actually where I wanted to start, with injuries. Like, how likely are you to get hurt as a runner? And I wanted to compare running with stuff that's also pretty accessible, so I looked at cycling and swimming. And there are lots of studies. They'll survey people about what they do and if they got hurt. So, like, one review will look at runners over a period of time to see, like, okay, how much did you run? What kind of injuries did you get? Another review will look at cyclists, and then swimmers.

• 3:57Speaker 02

  Okay.

• 3:58Speaker 00

  And when you look at these reviews side by side, what you find is that runners do get hurt more often.

• 4:05Speaker 02

  They do. So, it's not just in our heads. Runners actually are more likely to get injured.

• 4:10Speaker 00

  Yup.

• 4:11Speaker 02

  Okay. That's sort of satisfying, actually. It feels true.

• 4:15Speaker 00

  Right? The actual numbers, they kind of differ across studies. So one big review that I found said that typically half of runners get hurt every year with an injury that keeps them from running.

• 4:26Speaker 02

  Whoa. So about half of runners get injured every year?

• 4:31Speaker 00

  Yeah.

• 4:32Speaker 02

  Whoa, OK. That sounds pretty bad. And so what types of injuries were they getting?

• 4:39Speaker 00

  Yeah, so it's basically the stuff that you'd expect, right? From the knee down.

• 4:43Speaker 02

  OK.

• 4:43Speaker 00

  The best review that I could find on this looked at 42 studies. And found that generally, the most common type of injury was in the knees.

• 4:53Speaker 02

  OK.

• 4:54Speaker 00

  That was about 30%. Next up, about 20% of injuries were in the lower leg. So that's between your knee and your ankle, like your shin area. And then about 13% were ankle injuries.

• 5:05Speaker 02

  OK, but so generally, knees on down. Bad news for that part of your body if you're a runner.

• 5:10Speaker 00

  Yeah.

• 5:11Speaker 02

  Do we know why this is happening? Like, is it just that, like, impact of the grounds? Like, your body pounding on the pavement?

• 5:19Speaker 00

  Yeah, so that's one thing that we've thought for like ages, right? That it's wear and tear. After all, running can be super hard on your body. Every time your foot hits the ground, your knees absorb more than four times your body weight.

• 5:32Speaker 02

  Oof, OK.

• 5:34Speaker 00

  Yeah.

• 5:34Speaker 02

  That's a lot. It doesn't seem like that would be good for the joints.

• 5:38Speaker 00

  Right, it doesn't. But then, for some people, they run and they're just fine. So I wanted to know, what puts us at risk of getting hurt while we're running? And is there anything that we can do about it? So I called up a researcher who did a big study on this. His name is Dr. Rasmus Ostergaard Nielsen. He's an associate professor in the Public Health Department at Arhers University in Denmark. And he's also a runner himself. But he wasn't always as keen on it as he is right now. So I heard that you got into running because you came in dead last in a local race in your hometown.

• 6:15Speaker 06

  That was absolutely correct. I signed up for a road race with a friend. And I really, really had to fight my way through. And I came in second last in the race. And that really was the start of my running career.

• 6:33Speaker 00

  So since that humbling defeat in the road race, Rasmus has pretty much made running into his science career. And last year, he published this paper that looked at why so many runners are getting knocked off their feet by this sport.

• 6:45Speaker 06

  Many runners say, oh, I had this single run where I just ran too far and then my knee starts to hurt. And I thought, OK, this actually challenges the assumption that we have from clinical textbooks, which would describe that overuse injuries amongst runners develop gradually over time, over weeks.

• 7:09Speaker 00

  So Rasmus put together a study to look for patterns of when people got hurt. He and his team followed over 5,000 runners for about a year and a half and looked at how much they ran on average and then took a look at the times where they ran more than their average distance. And also took a look at how often they got injured after those runs. And what Rasmus found was pretty wild. If you run just a little bit farther.

• 7:32Speaker 06

  You increase your risk to up to 60%, larger.

• 7:36Speaker 00

  Oh, that's a lot.

• 7:37Speaker 06

  Yeah, that's quite a lot.

• 7:41Speaker 00

  Yeah, so for that big increase in risk, Rasmus saw it when people upped their distance just 10 to 30% over their longest run the week before. Just making that small change, that's when people had a 60% higher chance of injury.

• 7:56Speaker 02

  Whoa, so you gotta be really careful, like you're not messing around when you even just go that little bit more.

• 8:03Speaker 00

  Yeah, so Rasmus says that you can bump up your distance safely, but in order to do that, you shouldn't run more than 5% farther than what you usually do.

• 8:13Speaker 02

  Got it, 5% more, OK. So like, don't get too excited, like, just take it's really slow.

• 8:21Speaker 00

  Yeah, I mean, kind of like, don't get excited at all.

• 8:27Speaker 00

  It's really not that much more. I asked him about it. So I'm like, if I run 5K most of the time in my next training session, I want to run farther. That means I can't even go 6K.

• 8:41Speaker 06

  No, no, you can't. 6K would then be a 20% increase.

• 8:46Speaker 00

  I think that most runners would be really upset to hear this.

• 8:52Speaker 06

  Yeah, but but still, numbers doesn't lie. And if you want to be in the safe zone, then then you need to to reduce the length of of your running session.

• 9:02Speaker 02

  This is actually very satisfying. So I thought my husband was ramping up slowly, but he was not going that slow. So now I feel like we have an explanation for basically why he got so injured because he was going up, yeah, at least a mile every week. And apparently, that's crazy to do that much. So, OK.

• 9:21Speaker 00

  And obviously, there's individual differences here. You know, like, your friend might be able to do a little bit more running than you without getting hurt. But 5% is the general rule that Rasmus is suggesting.

• 9:32Speaker 02

  OK.

• 9:33Speaker 00

  And even Rasmus, who's an expert in this field, has a hard time with keeping himself from running more than he should, right?

• 9:40Speaker 06

  If a friend come and say, OK, Rasmus, should we go out on a long run? And and we should do that very fast. And I get excited. I lose my mind. And even though I know when I go out for this running session, this is totally stupid. I really shouldn't do this. And then I sustain an injury.

• 10:01Speaker 00

  Yeah. And actually, one of the reasons why we might have this impulse is that our body can kind of give us mixed signals here. Because there's this kind of cool thing that's going on when we run. So as you're putting pressure on your body, you get micro injuries, micro cracks in your bones, changes in the collagen of your tendons. And when those heal, you actually get stronger. So over time, running can be really good for your body. Like, runners tend to have less arthritis in their knees.

• 10:32Speaker 02

  OK, wait. So in general, you're you're running along, you're getting these little micro cracks. But that's actually a good thing because then when your body heals, it like builds back stronger?

• 10:42Speaker 00

  Yeah, but that process can take a while. You know, like, it can take bones months to heal and get stronger. And for tendons, it can be pretty similar, but it ranges. But there's this other part of our body that tends to adapt a lot faster, our cardiovascular system.

• 11:00Speaker 00

  So you might find that you start out like huffing and puffing, but then pretty quickly, maybe even within a matter of weeks, you might start to notice that you're breathing easier and your heart might not feel like it's beating out of its chest so much.

• 11:16Speaker 02

  So then you might get a little carried away because you're like, I can do this. I feel so much better. But you don't know about those microcracks in your bones.

• 11:23Speaker 00

  Or do you? Because your shin is acting up and you're just deciding, well, I want to keep running anyway.

• 11:28Speaker 02

  Right, right.

• 11:29Speaker 00

  So this little ramp up is important.

• 11:31Speaker 02

  OK.

• 11:31Speaker 00

  And a lot of people talk about your form here, you know, your stride. There is some evidence that switching from running on your heels to running on the balls of your feet can reduce the load on your knees. But at the same time, doing that could also shift more of that force onto your ankles and your feet.

• 11:51Speaker 02

  All right, so there's no secret stride that science is saying this will save you from getting injured, yet.

• 11:57Speaker 00

  Right. Like, overall, it's just not super clear that making these changes reduces your risk of getting injured. Rasmus told me that the slow ramp up probably makes more of a difference here.

• 12:07Speaker 02

  OK, good to know.

• 12:10Speaker 00

  And there's another big thing that you can do here to prevent yourself from becoming, you know, just another running statistic.

• 12:16Speaker 02

  Like what?

• 12:17Speaker 00

  Meryl, it might be time to start getting ass to grass and building up that booty.

• 12:24Speaker 02

  So the butt can save us if we have a really strong butt?

• 12:26Speaker 00

  Yeah, so there is this one study that looked at runners who were training for the New York City Marathon. And they got them to do these exercises to see how strong they were. It was stuff like planks, single leg glute bridges, pushups.

• 12:40Speaker 02

  So they would like see how long they could like hold one of these poses?

• 12:45Speaker 00

  Yeah, see how long they could hold the pose, see how many pushups they could do, stuff like that. And then they looked at who got hurt and who didn't while they were training to see if any of their strength made a difference. And what they found was that the only exercise that made a difference was the single leg glute bridge. It was the only one that cut down their injury risk.

• 13:06Speaker 02

  Wait, what's a single leg glute bridge?

• 13:09Speaker 00

  Okay, so in a regular glute bridge, you lie on your back with your knees bent and your feet flat on the ground. And then you push through your heels to like lift your butt off the ground.

• 13:21Speaker 02

  Okay, like a bridge pose in yoga.

• 13:24Speaker 00

  Yes, but with the single leg glute bridge, you're just doing it with like one leg instead of both on the ground.

• 13:31Speaker 02

  Okay, I can picture that.

• 13:33Speaker 00

  And people who could hold this for at least 20 seconds, specifically on their weaker leg, had a 64% lower risk of getting hurt while they were training.

• 13:42Speaker 02

  Why is the butt so important?

• 13:44Speaker 00

  So one explanation I've seen is that muscles in your butt help to keep your hip joints stable and also help to keep your hips and knees in proper alignment.

• 13:55Speaker 02

  Huh.

• 13:56Speaker 00

  Yeah, so when your butt muscles are weak, the body adjusts by moving in these like new ways that can put more force and like weight on your joints.

• 14:07Speaker 02

  Oh, interesting.

• 14:09Speaker 00

  Like your knees might rotate inward more or one hip might be higher than the other.

• 14:15Speaker 02

  They get a little wonky if the butt isn't like holding everything in place.

• 14:19Speaker 00

  Yeah, exactly. So if you're moving differently, then like basically the Jenga stack of your body is kind of off balance.

• 14:28Speaker 02

  Right, because it's like that's a critical piece in the Jenga tower. Um, the butt, it's right there in the middle. Yeah.

• 14:34Speaker 00

  Yeah.

• 14:36Speaker 02

  So important. Wow, newfound appreciation of the butt. Okay.

• 14:42Speaker 00

  And just generally, muscles are great shock absorbers. So strengthening all these muscles, you know, around your butt, your hips and your joints, they really help to stabilize everything and prevent injury.

• 14:52Speaker 02

  Okay, so do the booty exercises.

• 14:54Speaker 00

  Do the booty exercises. Yes. Yeah.

• 15:01Speaker 00

  So Meryl, that's kind of all we have to say about injuries. What did you learn?

• 15:07Speaker 02

  I feel like I learned a lot. You know, I know to do the booty exercises and that it's also way more likely that we'll get injured if we ramp up too quickly.

• 15:16Speaker 00

  You're a good student, Meryl.

• 15:17Speaker 02

  Yay. But okay, well, so I guess overall, my question is still like, then should I run? Like, do the pros outweigh the cons?

• 15:28Speaker 00

  That's coming up after the break.

• 15:29Speaker 02

  All right.

• 15:42Speaker 00

  Welcome back. I'm McKeddie Foster Keys here with Merrill Horn.

• 15:45Speaker 02

  Hi.

• 15:46Speaker 00

  And so far, we've talked about injuries, you know, all the reasons why you might not want to run. But now let's talk about the benefits.

• 15:53Speaker 02

  Yes, finally. All right, what are the good things?

• 15:56Speaker 00

  So for this, I talked to Professor Duxell Lee. He studies physical activity at the University of Pittsburgh.

• 16:02Speaker 07

  Pittsburgh, D.C., as in Washington, D.C.

• 16:06Speaker 00

  So DC did this huge study a while ago that was focused specifically on running and longevity. It looked at over 55,000 adults over 15 years. And what he found was basically that runners live longer.

• 16:19Speaker 02

  OK.

• 16:20Speaker 00

  Running was associated with significantly lower risk of death compared to not running. And here, they specifically looked at cardiovascular disease and something that's called all-cause mortality.

• 16:31Speaker 02

  OK. Oh, and both of those things were lower in the runners?

• 16:34Speaker 00

  Yeah, yeah, both of those things were lower.

• 16:36Speaker 02

  Nice.

• 16:37Speaker 00

  And DC told me that the reason why running increases longevity is because it does things like lower your blood pressure, improve your cholesterol, and improve your glucose levels. So all this stuff is super important for your heart.

• 16:50Speaker 02

  OK.

• 16:51Speaker 00

  It also can reduce chronic inflammation, which is linked to a whole bunch of diseases.

• 16:56Speaker 02

  I mean, it is nice to hear. It's not surprising.

• 16:58Speaker 00

  Yeah. Now, it's possible that people who are already healthy and therefore likely to live longer anyway, that they're also more likely to be runners.

• 17:08Speaker 02

  Oh, right.

• 17:09Speaker 00

  But the study did try to take that into account.

• 17:12Speaker 02

  OK. Well, that's really, I mean, I feel like that's so different from all the scary TikTok doctors that I've seen. Like, if it's overall going to make us live longer, it can't be that bad for us to run.

• 17:23Speaker 00

  But TikTok doctors are leading you astray, Merrill.

• 17:27Speaker 02

  Yeah.

• 17:28Speaker 00

  And it brought up another question for me, which is, like, how much do I actually have to run if I want to live longer?

• 17:35Speaker 02

  Oh, yeah.

• 17:36Speaker 07

  People may think no pain, no gain, you know, or the more, the better regarding exercise and health, right?

• 17:44Speaker 00

  But what DC found kind of turned that idea on its head. His study found that people who ran less than one hour per week basically got the same benefit as people who ran more than three hours per week when it came to longevity.

• 17:57Speaker 02

  Whoa.

• 17:59Speaker 00

  Yeah. Here's DC.

• 18:01Speaker 07

  I was surprised that doing more was not...

• 18:06Speaker 07

  You know, was not providing more benefits. You know, when I published that original paper, lots of serious runners were unhappy. Because, again, the benefits from pushing further was small.

• 18:19Speaker 02

  So it really doesn't matter. Like, you don't need to worry about running extra hard if what you're going for is like a boost in your longevity.

• 18:30Speaker 00

  Yeah, exactly. And you can even break that one hour of running down into just five to 10 minutes per day.

• 18:36Speaker 02

  Whoa, five to 10 minutes a day. That's it, that's all you need to do. Okay.

• 18:40Speaker 00

  Yeah.

• 18:40Speaker 02

  Nice.

• 18:41Speaker 00

  Uh, so for DC, this is the bottom line.

• 18:44Speaker 07

  Moving from sitting all day, like a computer 73, to adding even very small, very small amount of any type of physical activity will provide health benefits. That's for sure.

• 19:03Speaker 00

  And we should say that even though DC study looked at runners, this goes beyond just running. You can get these benefits from other kinds of cardio exercise, too.

• 19:13Speaker 02

  Okay, sure, right.

• 19:14Speaker 00

  And by the way, all this was especially interesting because there's this idea that our listeners brought up that running is bad for the heart.

• 19:22Speaker 02

  Hmm.

• 19:23Speaker 00

  But that's not true.

• 19:24Speaker 02

  Yeah, that... This doesn't seem like it dives with what you've been saying.

• 19:28Speaker 00

  Right.

• 19:29Speaker 02

  Okay.

• 19:30Speaker 00

  It seems like this does come from a little bit of evidence. You know, like, some studies suggest that men who run a lot have a higher risk of some heart issues.

• 19:40Speaker 02

  Oh.

• 19:41Speaker 00

  But that's men who run a ton, like 10 times more than the weekly recommended amount.

• 19:45Speaker 02

  Whoa, okay.

• 19:47Speaker 00

  Yeah, it works out to something like three hours per day.

• 19:50Speaker 02

  Whoa. So for that very specific group of men, you said?

• 19:55Speaker 00

  Yeah, men.

• 19:56Speaker 02

  Then they might have an increased risk for some heart issues. But for all the rest of us, we're okay. It's actually good for the heart.

• 20:03Speaker 00

  Yeah, so running, good for the heart. Overall, good for not dying.

• 20:09Speaker 02

  Looking pretty good.

• 20:10Speaker 00

  Exactly.

• 20:11Speaker 02

  OK, so it's good physically for our bodies. Are there any like, mental health benefits to running? Because it does feel amazing, like, that's why I run.

• 20:20Speaker 00

  We know that exercise generally is good for our mental health. There have been a few clinical trials that show that exercise can help treat depression. There's also some evidence that it can help with anxiety and ruminating thoughts. And on top of that, we do hear that there is something special that running can do for us.

• 20:39Speaker 01

  It's time to get high, runner's high, that is.

• 20:43Speaker 00

  So Merrill, have you experienced runner's high before?

• 20:46Speaker 02

  Yeah, for sure. I mean, sometimes it's, it's like, does kind of feel like a high. Like, I get this lightness, and I'm just kind of like bounding along. I'm picturing myself like, running next to the water, near my house. And it's just so beautiful, and the music is in my earbuds. And I'm just like, ah, like, it feels great. It's almost giving me life.

• 21:08Speaker 00

  Yeah. And by the way, you can get this feeling from other types of endurance exercise, like biking, for example. But we hear people talk about it most specifically with running.

• 21:19Speaker 02

  OK.

• 21:19Speaker 00

  And one study I found said that around 70% of endurance runners have reported having this runner's high at least once. So I wanted to know, what's going on in our brain when we get runner's high?

• 21:30Speaker 02

  Yeah, how does it happen?

• 21:31Speaker 00

  So, for a long time, scientists had one key suspect: endorphins. These are the natural opiates that our bodies make.

• 21:41Speaker 08

  They found the endorphins, and they were responsible, you know, for all the feelings, like eating chocolate.

• 21:49Speaker 00

  That's Dr. Michael Severs. He's a scientist at the Institute of Forensic Psychiatry and Sex Research at the University of Duisburg-Essen in Germany. And he told me that scientists found endorphins around the same time as the runner's boom, which started in the 70s. And since they were associated with all the things that can make you feel good, you know, food, sex, laughter, they were an obvious choice to explain runner's high. But then, this other suspect entered the ring. Here's Michael.

• 22:19Speaker 08

  So, in the 90s, they discovered a new system, the endocannabinoid system, which is everywhere in the body. And well, in the end, there was the question, okay, is it the endocannabinoids or the endorphins which are producing the runner's high?

• 22:37Speaker 00

  So endocannabinoids can also make us feel good? It might not surprise you, Meryl, to learn that they also work with the same receptors that contribute to other kinds of highs?

• 22:47Speaker 02

  Yes, the weed one specifically. And so how did Michael figure it out, which one it was?

• 22:53Speaker 00

  So he did a study where they basically blocked the receptors in our brains that get activated by endorphins.

• 22:58Speaker 02

  Huh.

• 22:59Speaker 00

  These are the same receptors that get activated if you take an opioid drug? And to block them, they actually use a medication that's given to people with substance abuse issues.

• 23:08Speaker 02

  Okay, if you take it and then you try to get high, you won't actually feel the high?

• 23:13Speaker 00

  Yeah, and so if runners take this pill and they don't get runner's high, then we know that the runner's high is the endorphins because the drug has blocked the endorphins, which means that it would block the runner's high.

• 23:25Speaker 02

  Okay.

• 23:25Speaker 00

  So what Michael Seame does is they have runners come into the lab, take either a placebo pill or the blocker, and then get on the treadmill for 50 minutes.

• 23:34Speaker 02

  Okay.

• 23:35Speaker 00

  And then before and after each session, they test for their mood and their anxiety.

• 23:39Speaker 08

  The blockage of the opioid systems did more or less not hinder runner's high. So we could demonstrate that the runner's high does not depend on endorphins.

• 23:53Speaker 02

  Does not depend on endorphins? It's not the endorphins. It's something else, like the endocannabinoids, I guess?

• 24:00Speaker 00

  Yeah, Michael thinks it's the endocannabinoids.

• 24:03Speaker 02

  Okay, so but why does he think it's endocannabinoids specifically and not just some other thing in the brain?

• 24:08Speaker 00

  Yeah, so Michael and his colleagues did look at endocannabinoids in the study, and they saw that they went up during the run.

• 24:15Speaker 02

  Okay.

• 24:15Speaker 00

  And then we also have mouse studies on this. There's this one study that looked at mice running on a wheel. And this time, some of the mice had their cannabinoid receptors either blocked or missing.

• 24:28Speaker 02

  Huh.

• 24:28Speaker 00

  They compared them to other mice that didn't. And they found that the mice with the blocked or missing cannabinoid receptors ran less than the other mice, by like 30 to 40%.

• 24:41Speaker 02

  Because they were not feeling the runner's high, I guess? Like they were, they were kind of bummed out. So like, why am I even running on this wheel? What's the purpose of life? I'm gonna stop. Oh, for my.

• 24:54Speaker 00

  Yeah. Bottom line, it seems like the endocannabinoids are the big deal here.

• 24:59Speaker 02

  Okay.

• 25:00Speaker 00

  But Michael doesn't think that endorphins are doing nothing while we run.

• 25:04Speaker 02

  Hmm.

• 25:05Speaker 00

  There is some evidence that endorphins can do other stuff. Like, we think that they can make your muscles hurt less while you're exercising or after.

• 25:13Speaker 02

  Okay, that makes sense.

• 25:15Speaker 00

  And then there's other stuff going on in our body. And one scientist told me that when you exercise, it's kind of like there's a chemical cocktail party going on up in your body.

• 25:24Speaker 02

  Mm-hmm.

• 25:25Speaker 00

  There's also dopamine, serotonin, adrenaline, and some other stuff, like, all dancing around in there.

• 25:32Speaker 02

  Great.

• 25:36Speaker 00

  Okay, so, the last thing I want to talk about is, if you haven't had a runner's high and you want to, what should you do?

• 25:43Speaker 02

  Oh, yeah. Yeah, can you, like, make it more likely that you'll feel a runner's high?

• 25:48Speaker 00

  Well, we don't have a ton of studies on how to get it specifically, but Michael did have some tips based on other studies about exercise and endocannabinoids.

• 25:57Speaker 02

  Okay.

• 25:59Speaker 00

  So, first, he said that you should aim for a heart rate that's between 70 to 80% of something called your age-adjusted max heart rate.

• 26:08Speaker 02

  But how, generally, like, how hard is that?

• 26:11Speaker 00

  It's pretty high intensity, like, pretty vigorous, but not your max. You don't want to be going, like, your hardest.

• 26:18Speaker 02

  That's helpful.

• 26:19Speaker 00

  And that's zone three running, for people who are familiar with zones.

• 26:22Speaker 02

  Got it.

• 26:23Speaker 00

  The other thing is that it probably won't happen if you're doing that bare minimum 10 minutes.

• 26:28Speaker 02

  Oh, you have to be running for a while, which makes sense to me. I feel like I don't really hit it until it's been, like, a good 20 minutes at least.

• 26:37Speaker 00

  Yeah, that's basically what Michael said, actually. He said you should be running at least...

• 26:41Speaker 08

  Like, 20 minutes? At 35 minutes, more or less, you're having the best mood results in the studies.

• 26:51Speaker 08

  And well, then it depends which is the best setting for you. For example, if you like to run in nature, then it should be like in nature. If you like your favorite music, you should listen to your favorite music. If you like to run in groups or alone.

• 27:08Speaker 00

  So that's where we're landing, Meryl. How do you feel about running now?

• 27:12Speaker 02

  I'm excited to get back out there. Like, it's, it is such a good feeling. And I'm excited that as long as you don't ramp up too quickly, you'll be healthier overall if you run.

• 27:24Speaker 00

  Oh, great.

• 27:25Speaker 02

  Are you gonna run more? Are you running right now?

• 27:28Speaker 00

  Yeah, I think this made me feel like, all right, like, I do want to get back into doing it more regularly. And I think that, like, the idea that, okay, I can just start with 10 minutes a day. It might not feel good to, like, my athlete's ego, but it's what will keep me safe and consistent. Oh, and, and, and now I can get a fat ass, too.

• 27:49Speaker 02

  Yeah. That's what we really learned, is that, like,

• 27:53Speaker 00

  That's what I learned.

• 27:54Speaker 02

  fat asses equal healthy running.

• 27:56Speaker 00

  Like, more so like a muscular ass, I guess. But either way.

• 28:00Speaker 02

  Sure, okay.

• 28:02Speaker 00

  I'm definitely gonna get back into it.

• 28:03Speaker 02

  All right, nice.

• 28:05Speaker 00

  Thanks, Meryl.

• 28:05Speaker 02

  Thanks, Akadi.

• 28:08Speaker 00

  That's Science vs. There are 76 citations in this week's episode. If you want to check them out, you can go to the link in our show notes.

• 28:25Speaker 00

  This episode was produced by Akadi Foster Keys, with help from Blythe Terrell, Michelle Dang, Rose Rimler, Meryl Horn, and Wendy Zukerman. We're edited by Blythe Terrell. Wendy Zukerman is our executive producer. Fact checking by Taylor White. Mix and sound design by Bobby Lord. Music written by Boomi Hidaka, Peter Leonard, Emma Munger, and Bobby Lord. Thanks to all the researchers we got in touch with for this episode, including Dr. Anita Eberl, Dr. Johannes Fliss, Professor Robert Otto, Dr. Hirofumi Tanaka, Dr. Peter Kokkinos, Dr. Marilyn Lynn Moffett and director Brian Farr. A big thanks to Joseph Lavelle Wilson and the Zukerman family. Science Versus is a Spotify Studios original.

• 29:09Speaker 00

  Listen for free on Spotify or wherever you get your podcasts. Follow us and tap the bell for episode notifications. We'll fact you next week.