BITESIZE | What Hunter-Gatherers Can Teach Us About Movement, Exercise and Ageing Well | Professor Daniel Lieberman #624

Why do we find it so hard to exercise despite knowing how good it is for us? Feel Better Live More Bitesize is my weekly podcast for your mind, body, and heart. Each week I’ll be featuring inspirational stories and practical tips from some of my former guests. Today’s clip is from episode 514 of the podcast with Professor of Biological Science and Professor in the Department of Human Evolutionary Biology at Harvard University, Daniel Lieberman. Daniel is the author of the brilliant book Exercised: Why Something We Never Evolved To Do is Healthy and Rewarding. In this clip, he reveals a fascinating truth: we didn’t evolve to exercise, but movement is key to living well. He challenges some common beliefs that exist around exercise and we discuss simple, practical ways of building sustainable movement habits into our daily lives. Thanks to our sponsor ⁠⁠⁠https://drinkag1.com/livemore Show notes and the full podcast are available at https://drchatterjee.com/514 Support the podcast and enjoy Ad-Free episodes. Try FREE for 7 days on Apple Podcasts ⁠⁠https://apple.co/feelbetterlivemore⁠⁠ For other podcast platforms go to ⁠⁠https://fblm.supercast.com. DISCLAIMER: The content in the podcast and on this webpage is not intended to constitute or be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or other qualified health care provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have heard on the podcast or on my website. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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

• 0:00Rangan Chatterjee?

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• 1:20Rangan Chatterjee?

  See all details at drinkag1.com/livemore. Welcome to Feel Better, Live More Bite Size, your weekly dose of positivity and optimism to get you ready for the weekend. Today's clip is from episode 514 of the podcast with Professor Daniel Lieberman. Daniel is the author of the brilliant book, Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding. In this clip, he reveals a fascinating truth: we didn't evolve to exercise, but movement is key to living well.

• 2:01Rangan Chatterjee?

  He challenges some common beliefs that exist around exercise and shares simple ways of building sustainable movement habits into our daily lives.

• 2:12Rangan Chatterjee?

  Everyone listening, I'm sure, has been hammered with the message that exercise, that physical activity is good for us, it's good for your body, it's good for your brain, it's good for your longevity, et cetera, et cetera, et cetera. So we've all got the knowledge that we possibly, probably should be moving more. Yet despite having that knowledge, so many of us are simply unable to put that into action regularly. And they start to blame themselves, they start to feel guilty, which is a huge problem that I see and have seen in practice for many years. So I wanted to start with this apparent paradox, this idea that exercise is something that

• 2:56Rangan Chatterjee?

  is really, really good for us on so many levels, yet at the same time, it's not necessarily something that we have evolved to want to do.

• 3:06Speaker 01

  Well, I would say we didn't evolve to do it at all. But yeah, that paradox is what really motivated my last book, Exercise. And maybe to answer your question, I'll give an anecdote, right? I was in Mexico doing some research and we were studying runners and people who run and actually discovered that most of the tarahumara, famous for running, don't actually run very much. But anyway, there was this one elder fellow who was a famous runner, did these very long distance races. And I was being a good anthropologist and I was asking all kinds of questions. And one of the questions was about training and I was beginning to realize that my concept of training was kind of alien to the tarahumara. And this guy just looked at me and I could tell, without even the translator saying anything,

• 3:48Speaker 01

  it's like, why would anybody run if they didn't have to? And I suddenly had this like, you know, this little epiphany, right? That our concept of exercise is alien to most people, right? And of course, I work in parts of the world where people are very physically active, they work hard. Here I was in a part of the world where people are hardworking farmers, they've got no machines, they've got no running water, they've got, you know, they're doing everything by hand. They occasionally do these long distance races, which by the way, are a form of prayer. That's why they do them. But the idea of going for a five mile run in the morning is nuts. Nobody does that. And I had this sudden, like this moment that, yes, we evolved to be physically active.

• 4:28Speaker 01

  But the kind of what we call exercise, which I define as voluntary, discretionary physical activity, it's planned for the sake of health and fitness, is a completely modern idea. And furthermore, if you're struggling, if you're a farmer or hunter gatherer, of course, we were hunter gatherers for most of our existence. If you're struggling to get enough energy, right? Struggling to feed your family, going for a five mile run in the morning, which is about 500 calories, is a terrible idea, right? Because those 500 calories is energy that you could use either on your own body or on your family, right? So the idea of doing unnecessary voluntary physical activity for no reason other than

• 5:10Speaker 01

  for your health and fitness, when you're already very physically active, is nuts. So we evolved to avoid physical activity, except for two reasons, for when it's necessary or when it's rewarding, right? So play is important and rewarding. Work is rewarding. A race might be rewarding. But getting on a treadmill in the morning, in a gym, you know, with fluorescent lights in a room with no air, et cetera, working as hard as you can, getting absolutely nowhere, there's a reason people dislike it. We never evolved to do that.

• 5:43Rangan Chatterjee?

  Yeah. I think that's a very powerful message today. And, you know, we're having this conversation in London. I'm rarely in London these days, but I came last week for a couple of days. And I think the underground station where I took a photo and posted on social media really illustrated your point, which was this beautiful flight of stairs. And on one side was an escalator going down, the other side an escalator going up. And literally, there was nobody on the stairs.

• 6:15Rangan Chatterjee?

  And both sides of the escalators were full. And I posted it not, and the first thing I said is, this is not a post about blame. But I thought it just beautifully illustrated the problem that we have in modern society, which is, why would you choose to take the stairs if you don't have to?

• 6:32Speaker 01

  Of course, it's an instinct to take the escalator. There are no escalators in the Stone Age. I think I can say that with definitive knowledge, right? There are actually a series of papers that have been now done in many different countries. And it doesn't matter where you are on the planet, when there's a staircase next to an escalator, only less than 5% of people take the staircase. And it doesn't matter what culture you are, it's a universal. It's because it's an instinct to, if you can save energy, why wouldn't you, right?

• 7:00Rangan Chatterjee?

  And I imagine that our hunter gatherer ancestors would also have taken the escalator had that option been available to them.

• 7:11Speaker 01

  Of course, and I think in addition to the fact that it's an instinct not to exercise, not to be physically active when it's neither necessary nor rewarding, that we also engage in this form of blame or shame, right? And you have to remember that we're asking people to overcome a very deep-seated instinct, and then people feel bad about themselves because they feel that, sure, I mean, they wake up in the morning and they think, well, yeah, I should go for a run, or I should do this, or I should lift some weights or something. And they don't do it for one reason or another, and then they feel really bad, right? And then they think that, well, they're lazy, there's something wrong with them. They're actually normal, right? They're completely normal human beings.

• 7:51Speaker 01

  And I think our job is to try to figure out how to help people be physically active, maybe not even exercise, but how to be physically active in a way that doesn't cause that kind of, you know, do it in a positive way rather than a negative way. And I think, and no offence, I know, because you're a physician, but you're a physician that cares seriously about prevention. But I think one of the problems is that we've medicalized exercise. We consider it a pill, right? And nobody likes to take pills, nobody likes to, you know, it doesn't make it fun. It doesn't solve that particular problem of overcoming that barrier. I mean, I'm sure you know that most medications, people don't take their medications either. So if they, people don't take their pills for diabetes, or this, that, or the other,

• 8:35Speaker 01

  why are they going to take the exercise pill?

• 8:37Rangan Chatterjee?

  Yeah, so perhaps a new PR angle is needed around exercise because it's often called the magic pill, isn't it, exercise and, you know, anti-cancer, anti-aging, anti-mental health problems, anti-everything.

• 8:50Speaker 01

  And I think we have this idea that you have to swim the English Channel or run a marathon or do a full triathlon, you know, Ironman, et cetera. Absolutely not necessary. Again, some exercise is better than none, more is generally better, but the benefits tail off.

• 9:06Rangan Chatterjee?

  It's interesting, the movements that, you know, our ancestors used to do regularly, and you've detailed them in depth in exercise, but they're not doing those things for the purpose of health and wellbeing. Like, that's a byproduct of doing what they need to do in order to survive, right? So it's a side effect.

• 9:31Speaker 01

  So, it is a side, I mean, you're right, they do it because they have to, right? They don't have, if you want to have dinner that day, you have to go out, you have to be physically active to get food, right? There's no Uber Eats in the Paleolithic, right? So it's true, physical activity was absolutely necessary. But I think that it's not just a side effect. I would argue that human beings, not only, like every other animal, benefit from being physically active, but there was special selection in human evolution for exercise to be unusually potent for enabling us to live long and healthy lives. And that's something that makes us different from every other organism. So to understand that, you have to recognize that we evolved from apes, right? Our closest living relatives are chimpanzees.

• 10:16Speaker 01

  And, you know, those shows on TV where you watch chimpanzees and they're doing all kinds of amazing, wonderful things? They do that, but very rarely. Most of the time chimpanzees just sit and eat, and then occasionally do some wild, crazy things, have sex, run around, throw things, and then they go back to eating and digesting. And so chimpanzees turn out to be basically couch potatoes. They're incredibly inactive. Typical chimpanzee walks two to three kilometers a day, takes basically as many steps per day as a sedentary American, sleeps 12 hours a night, and that's kind of a chimpanzee life. And then we evolved...

• 10:51Speaker 01

  For two things that are very special in this regard. One is that we evolved to be way more physically active. So we've got data on hunter-gatherers and farmers. These people are taking 15,000 to 20,000 steps a day. They're running, they're carrying, they're climbing, they're doing all kinds of things. So we evolved to be extra active compared to our ape ancestors. That's one thing. But the other thing that's important is that we also evolved to live very long lives after we stop reproducing. So almost every species on the planet stops, you know, basically doesn't last very long after they stop reproducing. That's because natural selection sadly cares about only one thing, and that's how many offspring we have, right? So once you stop having offspring, you enter what's called the selective shadow.

• 11:35Speaker 01

  I love that term, right? It means that you're basically irrelevant, right? There's no selection to keep you alive after you stop having babies. And humans are one of the very few species for which that's an exception. And that's because human grandparents actually play an important role in helping their children and their grandchildren. And what are they doing? Well, I mean, they're passing on knowledge and all that sort of thing, but they're also hunting and gathering, they're foraging. Grandparents in hunter-gather societies are out there every day. Grandmothers are digging up tubers and other sorts of things and bringing them back for their children and their grandchildren. Grandfathers are out there hunting and bringing back honey and all sorts of things like that. They're physically active.

• 12:16Speaker 01

  And so we evolved to live long lives, not retiring, going to the beach and, you know, playing canasta or whatever it is. We evolved to live long lives to be physically active. And in turn, I believe that there's been selection in our evolutionary history for the effects of that physical activity to turn on the mechanisms in our body that help us increase our health span, which means increases our lifespan. So physical activity isn't just something you do to get The food, it is. But the reason that exercise or physical activity is so healthy is that that that we've undergone selection for that physical activity to turn on all kinds of repair and maintenance mechanisms that keep us healthy.

• 12:59Speaker 01

  And because we never evolved not to be physically active, we never evolved to turn them on to the same extent when we're inactive. So instead of thinking of exercise as medicine, I would think of inactivity as being like poison or like not having air.

• 13:12Rangan Chatterjee?

  Yeah, so it's not necessarily that exercise or physical activity is good for us. It's that the lack of doing it is really harmful.

• 13:23Speaker 01

  Exactly. We call that a mismatch in evolution. It's an evolutionary mismatch, just like we never evolved not to breathe. Right? That's a problem, right? We never evolved not to be physically active. And when we stop being physically active, everything goes wrong. I mean, literally, because physical activity affects every system in our body.

• 13:40Rangan Chatterjee?

  Yeah, it's it's so fascinating. Where you were even writing about how a nursing mother, yes, she still does some gathering, I think. But you were sort of making the case that the grandmas are way more active. I thought that was really, really interesting because that's quite alien to the common belief, I would say, certainly in Western cultures, that you can kind of slow down a bit as you get older. And we have this modern phenomenon that's retirement, right?

• 14:10Speaker 01

  Yeah, they're digging, they're carrying, they're walking. This is what you do. And and it's rewarding, of course, but it's also necessary. And that and I think in turn, that physical activity is helps them live to be the to live to be grandparents in the first place. Think about it this way. In in the West today, a lot of people, as they get older, become less active. We know that from lots and lots of studies. And and that we we don't turn on those repair and maintenance mechanisms that keep us healthy. So we're more likely to get heart disease and diabetes and osteoporosis and Alzheimer's. And the list of various diseases is very long. But now we have medicine, people like you, kind of keep them going, right? And so we can we can enable us to live.

• 14:54Speaker 01

  We have reasonably long lifespans, even with a lot of chronic disease. So the average American, I think their lifespan is 78, 79. The average health span, the number of years that the average American lives without entering a period of chronic disability is about 60 something, 63. So the average American spends 16 years before they die. In a state of chronic disease.

• 15:17Rangan Chatterjee?

  Yeah. In terms of walking, there's a, you know, maxim, isn't there, that we should aim to have around 10,000 steps per day? What's your take on that?

• 15:29Speaker 01

  Oh, well, you know, that's a kind of a funny story. I'm not sure if you've covered that on this on your podcast before, but, you know, that 10,000 steps a day came from, there was this accelerometer that was created for the, in Japan, just before the Olympics in 64. And I, the story is that apparently in this company, they were sitting around the table and deciding what to call it. And apparently 10,000 is an auspicious number in Japanese. And they said, well, let's call it the 10,000 steps meter. And turns out it's actually not that bad, right? It's a, it's a, you know.

• 16:02Rangan Chatterjee?

  It's not bad as a recommendation.

• 16:04Speaker 01

  It turns out to be okay. So if that's a, if that'll help you get more steps in, so, you know, if you have one of those watches that makes sure you get 10,000 steps every day, fine. But, but we've, again, we've kind of medicalized it, right? We've turned it into a prescription. And we often talk about optimizing health or whatever. Well, it doesn't work that way, right? If you, if you look at, so my colleague, Aiman Lee at Harvard, has done a lot of work on step counts and health. And if you look at some of the graphs that she's published, for example, first of all, there's a lot of error around the mean, but if you're interested in, say, heart disease, the more steps you take, the better.

• 16:45Speaker 01

  3,000 steps is better than 0,000 steps and 5,000 steps is better than 3,000 steps.

• 16:49Rangan Chatterjee?

  Is there an upper limit?

• 16:51Speaker 01

  So far, I don't think she sees a limit for, for steps, it's just walking, right?

• 16:55Rangan Chatterjee?

  So like, if you could get to 15,000 or 20,000 steps, it's currently, from what we know, that's, we think that's going to help decrease your risk of heart disease.

• 17:03Speaker 01

  That's what, that's what her data show. But again, there's a lot of error, variation around the mean. So what hap, what your benefit might not be the same as my benefit.

• 17:10Rangan Chatterjee?

  Of course.

• 17:11Speaker 01

  But if you look at the, the data on step counts and say, all cause mortality. Hmm, it kind of evens out starting around 7,000 steps.

• 17:19Rangan Chatterjee?

  So, once you're hitting 7,000 steps a day, it's kind of like, look, you've got most of the benefit.

• 17:25Speaker 01

  Yeah, and if you did diabetes, you'd get a different curve, et cetera, et cetera. But again, there's a, there's a mean, but there's also incredible variance around the mean. So what might be good for you is not going to be the same thing as for me. Or if you're 50 versus if you're 20, or if you've had knee injury, or I could go on, right? So we prescribe it like, you know, how many aspirin you should take, or how many milligrams of such and such you should take. And it doesn't work that way, right? So maybe that helps some people, but I think other people, it makes them confused and agitated and, and stressed, right? It's yet another source of stress in their life.

• 17:59Rangan Chatterjee?

  Did you say before that some of these hunter gatherer populations that you have studied, that they're taking what 15,000 to 20,000 steps a day?

• 18:07Speaker 01

  That's correct.

• 18:08Rangan Chatterjee?

  Ish.

• 18:08Speaker 01

  Yeah, but that, but again, that doesn't mean that that's best for them, right? Just because hunter gatherers do something doesn't mean we should do it. It's not a prescription, right? Instead, these are populations that tell us about the normal range of human variation and, and how our world has changed, enabling us to now understand what's a mismatch, right? What, what is it that we're not adapted for, right? Because a mismatched disease is a disease that is more common or more severe because our bodies are inadequately or imperfectly adapted for this novel environment. And so these are ways of helping us identify the mismatches in our world and then, and then addressing them. So, so there is no one number of steps to take per day. Look, the evidence on exercise is pretty darn clear, right?

• 18:53Speaker 01

  Which is that, or physical activity, I should say, right? If, anything is better than nothing, right? If you're, if you're completely sedentary, just taking a few steps, you know, more steps a day, climbing the stairs, you know, parking your car further away from the shopping, anything is better than nothing. More is better, and at a certain point, the benefits seem to tail off, right? And, and, but trying to come up with a number.

• 19:20Rangan Chatterjee?

  Yeah.

• 19:21Speaker 01

  An optimum is not only impossible, I think it actually sends an incorrect message, right? That, that, that, that it's like a, like a medicine which you can prescribe in a particular dose. It just doesn't work that way. And I, and I think, and we also get this idea, it's like this magic pill, right? I mean, exercise is good for you. There's no question about it. Physical activity is good for you because if you don't do it, it's bad for you. But it, it won't prevent all disease. It decreases your vulnerability. So, people who are physically active are much less likely to get heart disease. They're much less likely to get diabetes. But, but they're not prevented from getting them. You can still get diabetes if you exercise. You can still get heart disease if you exercise. You can still get all these diseases.

• 20:03Rangan Chatterjee?

  It's about reducing risk.

• 20:04Speaker 01

  It reduces your risk. I would say it reduces your, that's the medical term. The evolutionary term is it reduces your vulnerability.

• 20:10Rangan Chatterjee?

  Yeah. So, looking back to what you've been saying throughout this conversation, the case you make in Exercised.

• 20:21Rangan Chatterjee?

  We've evolved to, to move every day, right? We, we've evolved to, as you say, these populations walking 15,000 to 20,000 steps a day. Again, you've made the point, it doesn't mean that we have to do that same level, but it's hard to think that we can get away without doing some degree of kind of walking, significant walking every day. And certainly if I, if I just reflect on, you know, you look at things through the lens of evolution. I look at things through the lens of what have I seen in practice over two decades? And, you know, yes, the research supports this, but time and time again, like, you know.

• 21:04Rangan Chatterjee?

  The people who do well from a whole variety of different conditions, whether they be physical health or mental wellbeing, you know, a commonality is that they're moving regularly. And if they're not, increasing it makes a big difference. I've seen it time and time again. And so

• 21:21Speaker 01

  And evolution explains why.

• 21:23Rangan Chatterjee?

  And evolution explains why.

• 21:24Speaker 01

  So you have the data and the experience, but you know, we have this old, this famous expression, you know, nothing makes sense in biology, except in the light of evolution. You could actually say, nothing makes sense, except in the light of evolution. And so it's the evolutionary story which explains why this is the case. And I think that the evolutionary perspective also helps us think creatively about it, too.

• 21:44Rangan Chatterjee?

  Yeah.

• 21:44Speaker 01

  Because we don't, we're not physically active. I mean, I could, I could have spent my entire day doing almost nothing. And I'm sitting in a chair here, I could have taken the subway here, et cetera, et cetera. And the lift up and all that sort of stuff. So we now created this weird thing called exercise because it's good for us. But when we do it, we're doing it. There's, there's no purpose for it, other than for the sake of exercise. And that is a kind of weird thing. And so, and because it's not fun, we, we try to divert ourselves while we're doing it to decrease how unpleasant it is, right? Make it as, as minimally unpleasant as possible, right? You know, we've industrialized it, we've commodified it, we've medicalized it, we've, you know, we've, and there's nothing wrong with industrialization or medicalization or commodification.

• 22:27Speaker 01

  But that takes away the, the real kind of, the purpose for it that, that could make it much more.

• 22:37Speaker 01

  I mean, I think it's why people enjoy sports, right? Because when you play a game of football or something, right? You're, you now have a purpose that's

• 22:44Rangan Chatterjee?

  Yeah.

• 22:44Speaker 01

  And, and, and most people don't think of going for a walk with a friend or playing a game of sports. They don't, not often think of it as exercise, right? They think of it as, as you're playing a game of football, or you're going for a walk with your friends. And, and that gives it purpose. And I think that's, I think, one of the, the arguments, one of the tricks that we should be using to try to help each other be more physically active. Give, make it, make it part of our lives.

• 23:08Rangan Chatterjee?

  Hope you enjoyed that bite-sized clip. Do spread the love by sharing this episode with your friends and family. And if you want more, why not go back and listen to the original full conversation with my guest? If you enjoyed this episode, I think you will really enjoy my bite-sized Friday email. It's called the Friday Five, and each week I share things that I do not share on social media. It contains five short doses of positivity, articles of books that I'm reading, quotes that I'm thinking about, exciting research I've come across, and so much more. I really think you're going to love it. The goal is for it to be a small, yet powerful dose of feel-good to get you ready for the weekend.

• 23:50Rangan Chatterjee?

  You can sign up for it free of charge at drchattity.com/fridayfive. I hope you have a wonderful weekend. Make sure you have pressed subscribe, and I'll be back next week with my long-form conversation on Wednesday, and the latest episode of Bite Science next Friday.