Harvard Neuroscientist: "If You Sit Like THIS, Watch Out! – It Destroys Your Body" | Dan Lieberman

1. 0:00 – 3:13

   Sitting isn’t the enemy—how modern chairs and long, unbroken bouts cause problems

   1. RCDr. Rangan Chatterjee0:00

      We have been told that sitting is the new smoking over the last few years. What's your take on sitting?

   2. DLDan Lieberman0:07

      Well, again, it's completely normal to sit, right? I mean, cows in the field sit. You know, moose sit. Chickens sit. Birds sit. Everybody sits. And, and humans are no different, right? And so when Dave Raichlen and Herman Pontzer and Brian Wood measured sitting among the Hadza, which are a population of hunter-gatherers that are, you know, the most studied because they're the easiest to study, they sit 10 hours a day. [laughs] Um, so the idea that, you know, sitting is this modern Western scourge is just not true. That said, there are important differences between how we evolved to sit and how people now sit today. Now, right now we're having this lengthy conversation, and I'm kind of glued to this chair. But, uh, so what we sit now in the West, we may sit long periods of time, but we tend to live... We also tend to sit for long, uninterrupted bouts.

   3. RCDr. Rangan Chatterjee0:54

      Mm-hmm.

   4. DLDan Lieberman0:55

      Hours at a time without getting up. But if you look at, at, um, at n- populations that don't have chairs, um, they, they interrupt their sitting bouts co- uh, constantly. They get up to tend the fire, to go pick up a kid, to do a little bit of this, to do a little bit of that. And so, so that's-

   5. RCDr. Rangan Chatterjee1:13

      Is that always to do stuff, or is it sometimes because if you don't have a chair, you might be sitting in a-

   6. DLDan Lieberman1:18

      Oh, absolutely

   7. RCDr. Rangan Chatterjee1:18

      ... position that becomes uncomfortable after 20 minutes?

   8. DLDan Lieberman1:21

      I think it's a combination of the two.

   9. RCDr. Rangan Chatterjee1:22

      Yeah. Okay.

   10. DLDan Lieberman1:23

       Exactly. So that's ... So, so, so they don't sit for long, uninterrupted bouts. That's one difference. And the other difference is that, um, um, they don't have... Like this chair I'm sitting in, I'm now leaning against the back, right? It's not... The chair has been designed to, you know, for ergonomically to have the, the least amount of work that my body's doing, right? And so that means that I'm not turning on a single muscle in my body now-

   11. RCDr. Rangan Chatterjee1:46

       Yeah

   12. DLDan Lieberman1:46

       ... except for I'm gesticulating and I'm using the, you know, my mouth, right? Uh, whereas, you know, the modern chair with a seat back didn't become common until the, the Industrial Revolution. Actually, the first mass-produced chair was produced in 1859, an important year for evolutionary biologists 'cause that's the year that The Origin of Species was published, right?

   13. RCDr. Rangan Chatterjee2:07

       Wow.

   14. DLDan Lieberman2:08

       And, uh, so, uh, uh, Thonet, a guy in Germany, produced the first... You know, the café chair with those bentwood?

   15. RCDr. Rangan Chatterjee2:14

       Yeah.

   16. DLDan Lieberman2:14

       That was the first industrialized chair. And now of course, chairs with backs are, are omnipresent. You go anywhere in the world and those plastic chairs are... You name it. You go anywhere on the planet, people have chairs, right? But that, this chair I'm sitting in and that you're sitting in, now we no longer have to use any back muscles-

   17. RCDr. Rangan Chatterjee2:30

       Mm

   18. DLDan Lieberman2:30

       ... to keep up our upper body. We're not squatting or sitting on the ground, so we're not using any of the muscles in our legs. And when you, when you... Even that little bit of muscle effort changes... Or, and also getting up every once in a while. So intermittent, you know, si- sitting for... You know, getting up every once in a while and also using chairs-

   19. RCDr. Rangan Chatterjee2:48

       Ac- more active sitting positions.

   20. DLDan Lieberman2:50

       Exactly. And also, you know, you're having to use your back to stabilize yourself or your quads or your hamstrings, et cetera-

   21. RCDr. Rangan Chatterjee2:55

       Mm

   22. DLDan Lieberman2:55

       ... to squat or sit on the ground. All of that's turning on your muscles. And you're not using a lot of energy, right? It's not gonna help you lose weight. But just turning on your muscles turns on all these genes, et cetera.

   23. RCDr. Rangan Chatterjee3:04

       Yeah.

   24. DLDan Lieberman3:05

       You're using up fat in your bloodstream. You're using up glucose in your bloodstream. You're doing all kinds of other things that makes that sitting much less harmful. So-

2. 3:13 – 5:04

   Active sitting hacks: breaking up sedentary time and using less-supportive seats

   1. RCDr. Rangan Chatterjee3:13

      And I think for, for me, Dan, that, isn't that really the key take-home from your work, which is let's study these populations. Let's observe what they're doing. That can give us an insight into perhaps how we have evolved to live and move and eat [laughs] and all these other things. But we're not gonna go back to that world, most of us. So what can we learn from them and then apply in our modern urban environments? And so what, what, what came to mind as you were describing that is about three years ago or so, you know, we're in London at the moment, but in, in my own podcast studio I've got a, I don't know if you'd call it a chair. It's called a Moveman. And it's the best thing I ever bought because it's basically, there's no back to it. I think it's like one of those medicine balls but with a stable base essentially. So I'm sitting there, um, having these long two-hour conversations, and I feel, my back feels amazing at the end of it because if I have to const- my muscles are having to do something to keep myself upright.

   2. DLDan Lieberman4:27

      Constantly. Exactly.

   3. RCDr. Rangan Chatterjee4:28

      And I, I don't give it s- I don't, I don't have one for my guests. They've got an ergonomic chair.

   4. DLDan Lieberman4:32

      [laughs]

   5. RCDr. Rangan Chatterjee4:32

      Because I'm like, well, if they're not used to that, they may be going all over the place and not be on the mic, right? So I'm like, okay, well, I'll give them a normal chair or a really nice ergonomic chair. But that has been transformative. So, so we can learn from the research that you and your colleagues do and go, okay, well, could we have sitting positions that are less... It's not making them uncomfortable, 'cause who wants to sit at a desk in an uncomfortable way? But using, having to use your back muscles whilst you're sitting at your computer typing, well, even that would make a difference.

3. 5:04 – 7:01

   Global “physical activity transition”: what happens when rural farmers move to cities

   1. DLDan Lieberman5:04

      Sure. So I, I agree. I mean, that's, that's one of the reasons I'm interested in this. But I'm also interested in not just people like you and me, but I'm also interested and concerned about the transition that's going on around the world as people transition from being subsistence farmers to living in cities, and to help them not make the mistakes that-

   2. RCDr. Rangan Chatterjee5:22

      That we've made

   3. DLDan Lieberman5:22

      ... we've made, right? So as people... We call this the, the, the, the physical activity transition, right? It's, so in, for example, we have a project in Rwanda now. We're looking at people as they move from being f- farmers out in the rural areas where they're, you know, they have no machines and no running water-

   4. RCDr. Rangan Chatterjee5:36

      Mm-hmm

   5. DLDan Lieberman5:36

      ... and no electricity, and then they move to Kigali, the big city, and all of a sudden their lives change overnight, right? How can we help that transition occur in a better way, right? 'Cause I think this has global implications.

   6. RCDr. Rangan Chatterjee5:47

      Yeah.

   7. DLDan Lieberman5:47

      Because, so, so this is not just for people in England. This is for people for everywhere. And, and, and if we can avoid these mismatches, again, we don't have to go back to, you don't have to be a hunter-gatherer.

   8. RCDr. Rangan Chatterjee5:59

      Mm.

   9. DLDan Lieberman5:59

      But just a simple thing like just changing the way you sit.Can be important. Or, or having a little, you know, your watch telling you to get up every f- once in a while to remind you just to get up or make a cup of tea or go use the bathroom or whatever. All of that is good

   10. RCDr. Rangan Chatterjee6:11

       Are people receptive? Like in, in those populations, you're saying that you're, you, you'd love to help them not make some of the mistakes that we have made. Um-

   11. DLDan Lieberman6:20

       Well, right now we're mostly studying what's going on.

   12. RCDr. Rangan Chatterjee6:22

       Okay

   13. DLDan Lieberman6:23

       And, and, and, and then hopefully having an impact in terms of public health, right? So, so like for example, in Kenya, working with the Kenya National Museum to do an exhibit on this sort of thing that's-

   14. RCDr. Rangan Chatterjee6:33

       Right

   15. DLDan Lieberman6:33

       ... in, in, in the Kenya National Museum is it, which is the big, you know, museum system in Kenya to try to, to try to, actually we're trying to use the enthusiasm for running in Kenya to kind of give a public health message about physical activity. Like you don't have to, you know, be like Eliud Kipchoge or whatever and run a, and win the b- London Marathon or the Boston Marathon or whatever. Just going out for a jog can be a great thing, or just o- other aspects of physical activity. So, so we're ... Yeah. So that's-

   16. RCDr. Rangan Chatterjee6:57

       Yeah

   17. DLDan Lieberman6:57

       ... yeah. This is a, this is an important message that the whole world needs to, to know.

4. 7:01 – 9:46

   The 10,000-step myth—and what step-count research actually shows

   1. RCDr. Rangan Chatterjee7:01

      In terms of walking, um, 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?

   2. DLDan Lieberman7:11

      [laughs] 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, uh, accelerometer that was created for the, in Japan just before the Olympics, uh, in '64. And I pa- the story is that apparently in this company, they were sitting around the table deciding what to call it. And, and apparently 10,000 is an auspicious number in Japanese, and they said, "Well, let's call it the 10,000 steps meter."

   3. RCDr. Rangan Chatterjee7:39

      Hmm.

   4. DLDan Lieberman7:40

      And turns out it's actually not that bad, right? It's, uh, it's, a, you know, hun-

   5. RCDr. Rangan Chatterjee7:45

      It's not bad-

   6. DLDan Lieberman7:46

      Yeah

   7. RCDr. Rangan Chatterjee7:46

      ... as a recommendation, I think.

   8. DLDan Lieberman7:47

      I mean, you know, it turns out to be okay. Um, so if, 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-

   9. RCDr. Rangan Chatterjee7:56

      Yeah

   10. DLDan Lieberman7:57

       ... every day, fine. But, but we've, again, uh, w- we've kind of medicalized it, right? We've turned it into a prescription.

   11. RCDr. Rangan Chatterjee8:04

       Mm-hmm.

   12. DLDan Lieberman8:04

       And we often talk about optimizing health or whatever. Well, it doesn't work that way, right? Um, if you, if you look at... So my colleague I-Min 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. 3,000 steps is better than 0 thousand steps, and 5,000 steps is better than 3,000 steps, and 7,000 steps is better, et cetera, et cetera, et cetera.

   13. RCDr. Rangan Chatterjee8:35

       Is there an upper limits?

   14. DLDan Lieberman8:36

       So far, I don't think she sees a limit i- for, this is for steps. It's just walking, right?

   15. RCDr. Rangan Chatterjee8:40

       So like if you could get to-

   16. DLDan Lieberman8:41

       The, the line-

   17. RCDr. Rangan Chatterjee8:42

       ... 15,000 or 20,000 steps, it's currently, from what we know, that's, we think that's gonna help decrease your risk of heart disease.

   18. DLDan Lieberman8:48

       That's what, that's what her data show.

   19. RCDr. Rangan Chatterjee8:50

       Okay.

   20. DLDan Lieberman8:50

       But again, there's a lot of error, variation around the mean.

   21. RCDr. Rangan Chatterjee8:52

       Sure.

   22. DLDan Lieberman8:52

       So what ha- what your benefit might not be the same as my benefit, right?

   23. RCDr. Rangan Chatterjee8:55

       Of course.

   24. DLDan Lieberman8:56

       There's a lot of variance around that mean. But if you look at the, the data on step counts in, say, all-cause mortality, hmm, it kind of evens out starting around 7,000 steps.

   25. RCDr. Rangan Chatterjee9:07

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

   26. DLDan Lieberman9:12

       Yeah. And if you did diabetes, you'd get a different curve, et cetera, et cetera. But again, there's a l- there's a mean, but there's also incredible variance around the mean. So what might be good for you is not gonna be the same thing as for me.

   27. RCDr. Rangan Chatterjee9:24

       Yeah.

   28. DLDan Lieberman9:24

       Or if you're 50 versus if you're 20 or if you've had knee injury or, I could go on, right?

   29. RCDr. Rangan Chatterjee9:30

       Hmm.

   30. DLDan Lieberman9:30

       So we prescribe it like, you know, how many aspirin you should take or how many-
5. 9:46 – 13:26

   Avoiding the “paleo fantasy”: using traditional populations to spot mismatches, not create rules

   1. RCDr. Rangan Chatterjee9:46

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

   2. DLDan Lieberman9:55

      That's correct

   3. RCDr. Rangan Chatterjee9:55

      ... ish?

   4. DLDan Lieberman9:56

      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? Hunter-gatherers also don't brush their teeth. Hunter-gatherers don't sleep on nice mattresses. Sh- are you gonna give up your, your, your, your mattress, right, and sleep on the ground? Hunter-gatherers don't g- get on airplanes. Hunter-gatherers don't have refrigerators. Hunter-gatherers don't use vaccines. Hunter-ga- I mean, I could go on, right? So the, the, uh, we call this a paleo fantasy, the idea that, that what hunter-gatherers do is a prescription for modern life. Ra- i- instead, it's that by studying h- h- hunter-gatherers and also farmers, most of my work I do actually with subsistence farmers. So subsistence farmers are people who tend to have no machines. They have, don't have, to do their work for, they have don't have tractors, they don't have generators.

   5. RCDr. Rangan Chatterjee10:42

      Okay.

   6. DLDan Lieberman10:42

      They don't have electricity. They don't have running water. So these are people who are, who are growing the food that they subsist on. So that's why we call them subsistence farmers.

   7. RCDr. Rangan Chatterjee10:50

      And, and where, which country are you studying these populations in?

   8. DLDan Lieberman10:52

      We've studied them in Mexico, we've studied them in Rwanda, we've studied them in Kenya.

   9. RCDr. Rangan Chatterjee10:56

      Okay.

   10. DLDan Lieberman10:56

       Uh, that's where the f- the three main places we've done that-

   11. RCDr. Rangan Chatterjee10:58

       Okay

   12. DLDan Lieberman10:58

       ... this kind of work. Anyway, so just because hunter-gatherers take X number of steps per day doesn't mean that's the number of steps you should take.

   13. RCDr. Rangan Chatterjee11:06

       Yeah.

   14. DLDan Lieberman11:06

       Right? Just because hunter-gatherers eat something doesn't mean that's what you should eat. Just because hunter-gatherers don't do something doesn't mean you shouldn't do it either. Instead, these are populations that tell us about the normal range of human variation-

   15. RCDr. Rangan Chatterjee11:19

       Mm

   16. DLDan Lieberman11:19

       ... 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?

   17. RCDr. Rangan Chatterjee11:28

       Mm-hmm.

   18. DLDan Lieberman11:28

       Because a mismatch 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. The, look, the evidence on exercise is pretty darn clear, right? Which is that i- or physical activity, I should say, right? If anything is better than nothing [laughs] 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? Um, and, and but trying to come up with a number-

   19. RCDr. Rangan Chatterjee12:17

       Yeah

   20. DLDan Lieberman12:17

       ... uh, 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, uh... 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.

   21. RCDr. Rangan Chatterjee12:46

       Mm.

   22. DLDan Lieberman12:46

       So physic- people who are physically active are much less likely to get breast cancer and, and many other kinds of cancer. Colon cancer. The list is very long. They're much less likely to get heart disease. They're much less likely to get diabetes. They're much less likely to get COVID, right? But, um, um, 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-

   23. RCDr. Rangan Chatterjee13:08

       Yeah

   24. DLDan Lieberman13:08

       ... all diseases if you're in-

   25. RCDr. Rangan Chatterjee13:09

       It's about reducing risk.

   26. DLDan Lieberman13:11

       It reduces your risk. Your... I would say it reduces your... That's the medical term. It- the evolutionary term is it reduces your vulnerability, right? Your, your, your vulnerability.

   27. RCDr. Rangan Chatterjee13:20

       Yeah.

   28. DLDan Lieberman13:20

       So risk is a, is a, is a statistical mess- me- measure, but it's, it doesn't really work that way for, for you and me.

6. 13:26 – 18:15

   Strength, muscle loss, and healthspan: why sarcopenia drives frailty with age

   1. RCDr. Rangan Chatterjee13:26

      Yeah. Many people are becoming aware these days of the importance of strength and lean muscle mass, particularly as they're getting older. I think that certainly is a public health message. At le- [laughs] at least in the online podcast world, it's getting out there that it's important. [laughs]

   2. DLDan Lieberman13:43

      It's incredibly important.

   3. RCDr. Rangan Chatterjee13:45

      Yeah. So can you explain why you think it's so important based upon what you've seen?

   4. DLDan Lieberman13:50

      So one of the... You know, as people live l- longer, right? Actually, we're not living all that much longer. The data for, uh, the hunter-gatherers, by the way, is that if they survive childhood, their mean age of mortality, of death, is between about 68 and 78. 78, by the way, is the life expectancy of Americans today, right? So-

   5. RCDr. Rangan Chatterjee14:11

      So it's not dissimilar.

   6. DLDan Lieberman14:12

      No. They're... It's pretty similar, right? But the difference is that they're not getting a lot of these chronic diseases that we get today in, in the Western world, right?

   7. RCDr. Rangan Chatterjee14:20

      So they may be liv- living to similar ages, but free from these afflictions that, that, that, you know, that reduce quality of life for so many people these days.

   8. DLDan Lieberman14:29

      Right. And the term we use is healthspan, right? So healthspan is the number of years you live without any serious disease or disability, right?

   9. RCDr. Rangan Chatterjee14:37

      Mm.

   10. DLDan Lieberman14:37

       And so their healthspan is basically the same as their lifespan, 'cause there's no medicine to keep them going, right? You know, once they get sick, they die, right?

   11. RCDr. Rangan Chatterjee14:44

       Mm.

   12. DLDan Lieberman14:45

       So we evolved to have a long healthspan, which means therefore to have a long lifespan. And, um, and one of the ways to extend your healthspan is to stay strong. What, what happens is that, you know, people, if they... You know, muscles are a use it or lose it tissue, right?

   13. RCDr. Rangan Chatterjee15:01

       Yeah.

   14. DLDan Lieberman15:02

       They're metabolically expensive. About... Well, you're, you're, you're clearly stronger than I am, but... So most people are about 30% to 40% muscle.

   15. RCDr. Rangan Chatterjee15:10

       Mm.

   16. DLDan Lieberman15:10

       People who do a lot of weights might be a little bit higher, right? But muscle's really expensive tissue. You have to eat a lot more calories per day because of all your muscle, right? We could... To, to pay for that, that extra muscle. So we evolved to u- to have muscle when we need it. So when you exercise, you know, do, do strength training exercise, you build up muscle. We also l- evolved to lose it when we don't need it, because it's energy that could go towards something else. Reproduction is what e- evolution cares about. So that's why w- it's a use it or lose it system. So as people become less active in, in, in high-income countries because they've got electric can openers and, you know, running water and elevator lifts, you know, they don't have to carry anything. Go to the supermarket, you have a shopping cart instead of carrying the food around, et cetera.

   17. RCDr. Rangan Chatterjee15:53

       Yeah.

   18. DLDan Lieberman15:53

       We have prams for the, for the carrying your children, right? I could go on, right? Uh, w- because we don't do any much strength anymore, we're losing... We lose muscle rapidly as we age.

   19. RCDr. Rangan Chatterjee16:04

       Mm.

   20. DLDan Lieberman16:05

       And that creates a condition that you know only too well called sarcopenia.

   21. RCDr. Rangan Chatterjee16:09

       Yeah.

   22. DLDan Lieberman16:09

       That's a medical jargon, but it's a good one because sarco is the Greek word for flesh, and penia is loss. So it's flesh loss. I love the term.

   23. RCDr. Rangan Chatterjee16:17

       [laughs]

   24. DLDan Lieberman16:17

       'Cause it really makes you think about it, right?

   25. RCDr. Rangan Chatterjee16:19

       Yeah.

   26. DLDan Lieberman16:19

       So people become sarcopenic. They, they lose muscle mass, and that sets in motion a vicious circle because when you're frail from h- loss of muscle, you suddenly lose the ability to do all kinds of things like get out of a chair, right? Or, or it gets harder and harder because you lose power, you lose strength, and, and that... And then you end up doing less of other things, and it sets in motion this, again, this vicious circle that makes you less and less active, which then sets in motion all kinds of other-

   27. RCDr. Rangan Chatterjee16:47

       Yeah

   28. DLDan Lieberman16:47

       ... consequences of physical inactivity. So healthy aging requires you to maintain your strength. It's really important.

   29. RCDr. Rangan Chatterjee16:54

       And the populations that you study, you mentioned before how grandfathers and grandmothers stay remarkably active compared to modern Western populations. They're not specifically doing, you know... [laughs] They're not doing their cardio and then their strength training and then their high-intensity training, are they? They're sort of... H- How... Have you seen that them maintaining their strength as they age?

   30. DLDan Lieberman17:17

       Well, well, we're trying to measure that now.
7. 18:15 – 25:04

   How much muscle is ‘enough’? Trade-offs, fiber types, and the need for both strength and cardio

   1. RCDr. Rangan Chatterjee18:15

      Yeah. I've often thought about the cost of muscle. And yes, we talk about maintaining strength and putting on muscle. You don't, though, need to become a bodybuilder and have, right, massively huge muscles. If you want to, nothing against that. I'm just saying that's not necessarily what we're talking about. The cost of muscle, like, if you're out and energy and food is scarce, and you don't have big refrigerators and freezers and store cupboards with loads of foods, if you put on loads and loads of muscle, you have to feed that muscle, which means you have to acquire more and more foods. So I was thinking, it's quite costly muscle, isn't it, to have it on your body?

   2. DLDan Lieberman19:00

      Very. Yeah, so and you also need extra protein and all that. So, so yeah, we evolved to be, we, we evolved to be e- economical, right?

   3. RCDr. Rangan Chatterjee19:08

      Mm.

   4. DLDan Lieberman19:08

      And by that I mean to have enough but not too much, right? So you want enough muscle so that you can... And you want, also you want varied muscle, right? We have muscle fibers that are good for endurance, but they don't produce a lot of power. Those are the slow twitch fibers. And we have muscles that are good for power and, and, and speed, but they're, they're not good for endurance. The-

   5. RCDr. Rangan Chatterjee19:28

      Mm

   6. DLDan Lieberman19:28

      ... and those are the type, you know, they're the fast twitch. And we have the kind of intermediate muscle fiber types. And you need a good mix, right?

   7. RCDr. Rangan Chatterjee19:33

      Mm-hmm.

   8. DLDan Lieberman19:33

      You need m- mostly slow twitch for aerobic long distance endurance, for the walking, the running, et cetera. But you also need some fast twitch muscles too, right?

   9. RCDr. Rangan Chatterjee19:42

      Mm.

   10. DLDan Lieberman19:42

       And, and, um, and you also want to wire up your nervous system to your muscles kind of properly.

   11. RCDr. Rangan Chatterjee19:49

       Mm.

   12. DLDan Lieberman19:49

       And one of the things that physical activity does, exercise, sports, training, all that does is that you learn that you can actually turn on more muscle fibers with your- with a nerve than, than, than before. You can train your nervous system to be more efficient in how you use your muscles. It's all k- it's all a kind of a mix, but, but a- but again, you're quite right. You know, body, you know, bodybuilding, that kind of stuff, is actually deleterious, right? Having more muscle than you need is actually a cost. Everything's a trade-off, right? So, so too much muscle is actually a problem, as is too little. There's a balance, right?

   13. RCDr. Rangan Chatterjee20:21

       Is too much muscle only a problem when you can't feed it with enough calories?

   14. DLDan Lieberman20:29

       That's right, yeah. So, uh, but which is, which was n- n- normal until very, very recently.

   15. RCDr. Rangan Chatterjee20:33

       Yeah. So l- let's say you-

   16. DLDan Lieberman20:34

       So I tend to think in evolutionary terms, yeah.

   17. RCDr. Rangan Chatterjee20:36

       Yeah, so, so, you know, one of the things a lot of the longevity movement is kind of trying to educate people on is this idea that you, you know, your, your muscle mass is going to go down after the age of 30 unless you do something significant about it, okay? If you're not paying attention and doing something, it's gonna start declining. Can you slow down the rate of decline?

   18. DLDan Lieberman20:56

       Yeah. And the good news, it's easy. You just, [laughs] just do weights a few times a week.

   19. RCDr. Rangan Chatterjee21:00

       Yeah.

   20. DLDan Lieberman21:00

       You don't have to do that much.

   21. RCDr. Rangan Chatterjee21:01

       But-

   22. DLDan Lieberman21:02

       [laughs]

   23. RCDr. Rangan Chatterjee21:02

       ... I guess-

   24. DLDan Lieberman21:03

       [laughs]

   25. RCDr. Rangan Chatterjee21:04

       ... let's say you, you, you go and really, really take this to heart and go, "Right, I'm gonna put on loads and loads of muscle." I was thinking, you know, every time you eat food, depending on what you eat, there is some sort of, uh, cost to the body. There's a, there, there is a, uh, bolus of inflammation to a certain degree, which your, your body has to manage, right? So then-

   26. DLDan Lieberman21:26

       Yeah. You're also turning on anabolism and catabolism. You're, you know, I'm sorry, those are jargon, but you're, you're, you're going back and forth between building tissue and d- and using energy and, and, and, and yeah, it's complicated.

   27. RCDr. Rangan Chatterjee21:37

       Yeah. So, so I kind of think g- c- 'cause I feel we can, you know, as you mentioned, you, you publish this paper in Nature in 2010 on, um, minimalist, uh, shoes or, or barefoot walking and running, right? And then people take it to an extreme, and they start trying to do marathons in barefoot shoes, having never been in them before, right? I guess what I'm trying to get to is, are we potentially at risk of taking the message... I've got to be very careful how I phrase this because sarcopenia is real, and it's causing a lot of problems. So clearly it's better for people to focus on putting on muscle. But are there some people who perhaps are overdoing it and therefore having to overeat and turn on all those mechanisms every time they eat, which potentially could become-

   28. DLDan Lieberman22:22

       Yeah

   29. RCDr. Rangan Chatterjee22:22

       ... problematic for their longevity?

   30. DLDan Lieberman22:23

       Yeah.
8. 25:04 – 29:47

   Sponsor break (AG1) + defining ‘cardio’ and the Finnish athlete evidence

   1. RCDr. Rangan Chatterjee25:04

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   2. DLDan Lieberman26:43

      People who do strength training, fine, but don't skip the cardio. You need both.

   3. RCDr. Rangan Chatterjee26:47

      And what do you mean by cardio?

   4. DLDan Lieberman26:49

      E- Cardio is any kind of physical activity that, that, that, that requires you to increase your volume, cardio ... your, your, your, your, your output. So swimming, walking, running, volleyball, game of soccer, all that.

   5. RCDr. Rangan Chatterjee27:02

      Yeah.

   6. DLDan Lieberman27:02

      And some, some sports are mixed, like s- rowing, for example. I've, I've got a ... I recently bought a rowing machine, and I absolutely love it. It's, like, my favorite new form of cross-training, right? Rowing is kind of a mix of both aerobic, but also-

   7. RCDr. Rangan Chatterjee27:14

      Yeah

   8. DLDan Lieberman27:15

      ... there's some strength involved, right? Uh, that's one of the reasons why I love it. So if, if ... There's a famous study that was done on Finnish athletes. So Finland's one of those countries where they have fantastic national healthcare system.

   9. RCDr. Rangan Chatterjee27:24

      Yeah.

   10. DLDan Lieberman27:25

       And they have data on everybody in the whole country. And they looked at the, um, uh, aging of Finnish athletes who were strength athletes versus, you know, weightlifters versus, like, cross-country skiers and runners. Finland is famous for both, obviously. Uh, versus the average everyday Fins, right? And it turns out that the, um, that the, the weightlifters who didn't do much cardio actually had as worse h- or sometimes worse health outcomes as sedentary Fins. They weren't getting the benefit of the cardio that the aerobic athletes, th- the, the endurance athletes were getting.

   11. RCDr. Rangan Chatterjee28:03

       Wow.

   12. DLDan Lieberman28:04

       And there, and there, and there are other stu- studies which kind of showed the same thing. So again, nothing wrong with strength training, but don't ... The trade-off is don't only do strength training and not do some cardio. You need to do both.

   13. RCDr. Rangan Chatterjee28:14

       And then, then I think looking back to what you've been saying throughout this conversation, the case you make in Exercised, like, we've evolved to, to move every day, right? We, we've evolved to, as you say, these populations walking 15 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, [laughs] the people who do well from a whole variety of different, uh, 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 that's-

   14. DLDan Lieberman29:24

       And evolution explains why.

   15. RCDr. Rangan Chatterjee29:25

       And evolution explains why.

   16. DLDan Lieberman29:26

       So, so you have the data on, and the, 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-

   17. RCDr. Rangan Chatterjee29:36

       Yeah

   18. DLDan Lieberman29:36

       ... of evolution. And so it's the evolutionary story which explains why this is the case.

   19. RCDr. Rangan Chatterjee29:40

       Yeah.

   20. DLDan Lieberman29:40

       And I think that the evolutionary perspective also helps us think creatively about it, too.

9. 29:47 – 33:10

   Is there an upper limit to exercise? Marathons, ultrarunning, and the real trade-offs

   1. RCDr. Rangan Chatterjee29:47

      Yeah. You mentioned about is there an upper limit to exercise, and, um, that some of this data on ultra-marathon runners doesn't appear to suggest that there is, from that data at least, and you've, you, you acknowledge that they're small sample sizes. But again, just, just as with sitting where you said, yes, although, um, the Hadza tribe are sitting, you know, similar amounts to what we are sitting each day, the way in which they're sitting is fundamentally different. You can make the same case when we're trying to study exercise and, you know-You know, are marathons harmful, right? For example, if someone was to pose that question, 'cause some people have, saying, you know, a marathon's too much, right? But the point I'm trying to make is that let's say what does running a marathon mean? Well, it means you're completing 26.2 miles, okay? You can do that in a variety of different ways. You can be hell for leather the whole time. You may struggle, but you could be [laughs] in one of those top heart rate zones, or you could be doing it in a very, um... You could, in theory, do it in a, in a low cardiac, uh, sort of fitness zone under your lactate threshold, where you're probably putting, uh, minimal stress on your body or at least less stress. So we c- although both people have completed a marathon, you could make the case that, well, the impact on their body's gonna be completely different because of how they've done it.

   2. DLDan Lieberman31:09

      Absolutely. You know what? I've run a lot of marathons, right? And I can tell you, it's so much more fun to be at the end of the pack, right? The guys who are, you know, and the women who are, like, trying to win, right? They're not having any fun at all.

   3. RCDr. Rangan Chatterjee31:20

      Yeah.

   4. DLDan Lieberman31:20

      They're looking at their watches all the time. They're looking at their splits.

   5. RCDr. Rangan Chatterjee31:22

      They're pushing it.

   6. DLDan Lieberman31:22

      They're worrying about, they're worrying about their gels and their hydration, and this, that, and the other. They're... You know what? If you're just, like, r- running to finish it c- maybe 'cause you're running for a charity, 'cause it gives you a purpose, which I think is also a wonderful thing about the modern marathon. I mean, the London Marathon is the biggest single-day charity event-

   7. RCDr. Rangan Chatterjee31:38

      Yeah

   8. DLDan Lieberman31:38

      ... in the world.

   9. RCDr. Rangan Chatterjee31:38

      I know.

   10. DLDan Lieberman31:38

       It is a wonderful party. I've been to it twice. It's just amazing, right? See these people having a great time, and you watch the guys at the beginning and the women at the beginning walk across the finish line, 'cause I've also sat at the finish line.

   11. RCDr. Rangan Chatterjee31:49

       Yeah.

   12. DLDan Lieberman31:49

       They're stone-faced. They're like, you know, they're just relieved. They're like, "Ah."

   13. RCDr. Rangan Chatterjee31:52

       Yeah.

   14. DLDan Lieberman31:53

       They did it. You watch the, the charity runners that come in, and they're just... They're the happiest people on the planet, right? They're-

   15. RCDr. Rangan Chatterjee31:58

       Yeah. It's gonna have a different impact

   16. DLDan Lieberman31:59

       ... they're, they're having a great time, and they've, they've did it. They made it. Now, now, now, does... Is the, uh, the, the more fundamental question is, is the... Do you need to run a marathon to get those health benefits? And the answer is most definitely not.

   17. RCDr. Rangan Chatterjee32:11

       Yeah, agreed.

   18. DLDan Lieberman32:11

       Ma- [laughs] marathons are, are, are a challenge. That's why they're, that's why they're such a big deal. It's hard to run, and to... The training is really the hard part, right?

   19. RCDr. Rangan Chatterjee32:18

       Mm-hmm.

   20. DLDan Lieberman32:18

       Training to run 26.2 mile, and it does put a toll on your body. You have this, you know, cardiac troponin breakdown, and I could go on all the technol- you know, the technical details. Yeah, it's a stress on your body. Um, but you know, it's, there's no evidence that it's bad for you, but do you need to do it? Absolutely not, and I think we have this idea that you have to swim the English Channel or run a marathon-

   21. RCDr. Rangan Chatterjee32:38

       Mm

   22. DLDan Lieberman32:38

       ... or do a full triathlon, you know, Ironman, et cetera. Um, absolutely not necessary. Again, some exercise is better than none. More is generally better, but it, the benefits tail off.

   23. RCDr. Rangan Chatterjee32:50

       Yeah.

   24. DLDan Lieberman32:50

       And I, and there's always a trade-off, and the, I think the biggest trade-off for, like, marathons or triathlons is the toll on your family, right? [laughs] You know? All that time out training was, you know, time that you don't spend with your loved ones or, or whatever.

   25. RCDr. Rangan Chatterjee33:03

       Mm.

   26. DLDan Lieberman33:03

       Uh, so there, there can be... You know, everything has a trade-off-

   27. RCDr. Rangan Chatterjee33:06

       Yeah

   28. DLDan Lieberman33:07

       ... and, and, and, and extreme endurance sports are no exception.

10. 33:10 – 42:22

    Cancer as a ‘disease of high energy’: exercise as an off-switch for growth signals

    1. RCDr. Rangan Chatterjee33:10

       Let's talk about another mismatch disease, uh, cancer. You call this mismatch disease, and you specifically say that it's a disease of high energy.

    2. DLDan Lieberman33:20

       Hmm. This is important.

    3. RCDr. Rangan Chatterjee33:21

       What do you mean by that?

    4. DLDan Lieberman33:22

       So cancers are... So I'm an evolutionary biologist, right? So I think of cancer from an evolutionary perspective, and for me, cancers are a kind of evolution that's gone wrong in the body. It's a kind of natural selection. When a s- group of cells suddenly acquires set of mutations, more than one-

    5. RCDr. Rangan Chatterjee33:41

       Mm

    6. DLDan Lieberman33:41

       ... that now enable them to out-compete other cells. They don't turn themselves off. They take a... They, they, they take energy from other cells.

    7. RCDr. Rangan Chatterjee33:49

       Mm.

    8. DLDan Lieberman33:49

       They're now competing with the other cells in your body. It's a form of natural selection in the body that doesn't benefit the host, but it's benefiting those particular cells. And what is it that makes those cells able to do that, right?

    9. RCDr. Rangan Chatterjee34:04

       Mm.

    10. DLDan Lieberman34:04

        Well, it's generally more energy, right? So think about the causes, you know, the, the things that we know are, are, are, are help fight cancer or the things that we know that cause cancer. Well, high levels of, of body fat, right? People with obesity are much more likely to get cancer. People who have high levels of circulating insulin. Insulin is a, is a hormone that makes things, you know, turns things on. Cancer is about the on switch is off way more than the off switch.

    11. RCDr. Rangan Chatterjee34:31

        Mm.

    12. DLDan Lieberman34:31

        That's basically what's going on. Hormones. There again, hormones like estrogen, progesterone, testosterone, they're turning the on switch on, right? Cancer, the on switch is on so much that these cells are producing molecules that have caused damage. You get more mutations. They're, they're, they're, they're, um, you know, you... I don't know if you've talked about mTOR and rapamycin on the show really.

    13. RCDr. Rangan Chatterjee34:52

        Not lately, no.

    14. DLDan Lieberman34:52

        But, but, but that, that's a, that's the molecular mechanism. That's the off switch, right? So, so, so when we look at populations that move from low-energy environments to high-energy environments, cancer rates go up. Um, and we can see the mechanisms and, and, and think about physical activity. That turns down cancer rates amazingly. People, women who get just basic levels of physical activity, 150 minutes a week, the estimates are there's 30 to 50% lower lifetime risk of breast cancer. Let me say that again. 30 to 50% lower lifetime risk of bre- breast cancer from just basic levels of physical activity.

    15. RCDr. Rangan Chatterjee35:29

        Wow.

    16. DLDan Lieberman35:29

        Why don't more of us know this important statistic? Colon cancer, it looks like, like 60% decrease in, in, in, in, in, in incidence rate for people who are more physically active. I could go on, right? And, and that... And why is it? Because physical activity is essentially turning the off switch, right?

    17. RCDr. Rangan Chatterjee35:47

        But again, flipping it like you did before, yes, technically physical activity is decreasing those levels of cancer, but you could also look at it the other way and go, we've evolved to move. When we, when we don't move, we increase our rate of cancer. [laughs]

    18. DLDan Lieberman36:05

        Exactly. Exactly.

    19. RCDr. Rangan Chatterjee36:07

        Nice.

    20. DLDan Lieberman36:07

        I mean, yeah, I mean, that's, that's exactly the... You're absolutely right. So, so the mismatch is not being physically active. When we're not physically active are, are... Again, remember what, what's life all about? It's about taking in energy and having babies. So when we have extra energy, our bodies are gonna use that forFor, for building. Like for, for making babies, for building tissues, for whatever. So we, you know... So women, for example, who are sedentary, th- they all of a sudden have this extra energy they're not using on physical activity, so what do they do? They increase their estrogen and progesterone levels. Th- those, those experiments were first done by my colleague Peter Ellison at Harvard-

    21. RCDr. Rangan Chatterjee36:42

        Mm

    22. DLDan Lieberman36:42

        ... who showed that women who ran, uh, 20 kilometers a week, so they're spending 180 calories a day, this is not high levels of a- running, right? Had 50% lower rates of progesterone and estrogen during the second half of the menstrual cycle. Now, these women were not infertile. They were not having trouble conc- conceiving. You could say exercise is lowering their progesterone levels, but I would actually say it's the reverse. Being inactive, so the body says-

    23. RCDr. Rangan Chatterjee37:09

        Yeah

    24. DLDan Lieberman37:09

        ... "Oh, I've got all this extra energy. I'm gonna shunt that energy towards reproduction."

    25. RCDr. Rangan Chatterjee37:13

        Yeah.

    26. DLDan Lieberman37:14

        And because after all, that's what it's all about, right? So, so and now you have the higher levels of estrogen, higher levels of progesterone, those increase cancer rates. And, uh, physical activity also, again, we've talked about repair and maintenance, right? The, the energy that you allocate when you're physically active... After I exercise, right? I, I ran this morning ar- around the Thames. I did probably about eight miles, right? Um, my body's metabolism is still elevated from that morning run for sure. It's probably 3, 4% higher now than it would be if I hadn't gone for that run. And what's that higher metabolism doing? It's not, I'm not replacing the energy [laughs] that I spent running. I'm turning on all kinds of mechanisms throughout my body that are repair and maintenance mechanisms. One of the things I've done is I've increased the number of natural killer cells in my body.

    27. RCDr. Rangan Chatterjee38:02

        Mm.

    28. DLDan Lieberman38:02

        Right? Now, natural killer cells, I love the term, right?

    29. RCDr. Rangan Chatterjee38:04

        Yeah, me too.

    30. DLDan Lieberman38:05

        It's very warlike, right? But natural killer cells are a part of our immune system that, um, that are, that are all... They're swimming around my body all the time, and one of the things they do is they look for cells that have cancer, and they he- they identify and get rid of cells with cancer. So I've turned up my immune system to help fight, among other things, cancer in my body, but it wasn't that the exercise, you know, was-
11. 42:22 – 45:49

    Fasting in traditional societies: not a protocol, but a consequence of food scarcity

    1. RCDr. Rangan Chatterjee42:22

       What, what did you see, uh, in relation to fasting in some of these hunter-gatherer or more traditional populations?

    2. DLDan Lieberman42:28

       Well, they just don't eat all the time. I mean, look, in my building, right, you know, um, there's a snack machineThere's, uh, right at the bottom of the stairs, right?

    3. RCDr. Rangan Chatterjee42:36

       This is in Boston?

    4. DLDan Lieberman42:37

       Yeah, uh, in my, my building at Harvard, right?

    5. RCDr. Rangan Chatterjee42:39

       Yeah.

    6. DLDan Lieberman42:39

       So if I'm, if I'm hungry and I, I'm, like, a little, you know, I'm working on a paper or, you know, something, you know, or upset by my colleagues or whatever, and I get ... You know, I'm stressed. And stress makes you hungry. Cortisol-

    7. RCDr. Rangan Chatterjee42:54

       Mm

    8. DLDan Lieberman42:54

       ... it ma- makes you hungry, right? Um, I can just run down to that s- machine and get all kinds of crap, [laughs] right? All kinds of ultra-processed junk, right? Full of sugar and whatever. Um, and, and it satisfies my craving. It's not gonna ... It's gonna make me hungrier later on. But if you're in a subsistence population or if you're a hunter-gatherer and you're hungry, you have to [laughs] go out and either find the food that you're gonna eat, or if you're a farmer, you have to go and cook it and prepare it and whatever and get it from your, you know, the silo or whatever. You, you're just not surrounded by food, and you're not surrounded by high energy food.

    9. RCDr. Rangan Chatterjee43:29

       So to me, you don't see them necessarily practice, um, a form of fasting or restricted eating window or one day a week where they would reduce their calorie intake. Nothing like that. It was more, it was kind of inbuilt.

    10. DLDan Lieberman43:42

        They, they have no choice, right? You know what I mean?

    11. RCDr. Rangan Chatterjee43:43

        Yeah.

    12. DLDan Lieberman43:43

        Look, if they could eat as much as we do, they would, absolutely. Uh, when I ... The populations I work with, people are always hungry, and they're always asking for food.

    13. RCDr. Rangan Chatterjee43:51

        Hey, guys. I really hope you're finding this useful. If you are and you want more content like it, please do check out my book, Make Change That Lasts: Nine Simple Ways to Break Free from the Habits That are Holding You Back. It's in all the usual places as a paperback, e-book, and as an audiobook, which I'm narrating. Now, back to the video.

    14. DLDan Lieberman44:13

        I'm gonna tell you a funny anecdote. Um, so, uh, once I spent about seven or eight days with a group of hunter-gatherers, with, uh, some colleagues.

    15. RCDr. Rangan Chatterjee44:20

        Where was this?

    16. DLDan Lieberman44:21

        This is in, in Tanzania. And, um, and we had ... You know, we came with a few Jeeps and full of food, et cetera. And we spent a wonderful time with this, these wonderful, these, these folks. And they were very kind and whatever. And the last night we s- we, you know, we thought, "Let's have a party." And we cooked everything that was left that we had. All the food left. 'Cause we were just h- heading back to town, right? And so the ... We had this cook with us, and he made ... You know, he boiled every bit of rice that we had. And he made some cakes, which he smeared with jam. And he had ... I mean, it was like, it was an amazing feast, right? And I've never seen people eat so much. I mean, [laughs] they ... And it was like a paleo diet nightmare.

    17. RCDr. Rangan Chatterjee45:02

        [laughs]

    18. DLDan Lieberman45:02

        They ate so much rice and cake and whatever, and they went back for seconds and thirds. There was nothing left at the end, right? Um, why? Because they're hungry. And, and all of a sudden they had this bounty of food. Whereas you, you and I might like, "Okay."

    19. RCDr. Rangan Chatterjee45:15

        Yeah.

    20. DLDan Lieberman45:15

        "I don't need to eat thirds," right? But they, they, they were, they were s- they, they were happy. And then we, we danced for hours and hours later, right? But, um, um, you know, when you're in a, if you're in a situation where food is, is always in short supply, you're always gonna eat what's available to you.

    21. RCDr. Rangan Chatterjee45:31

        Yeah.

    22. DLDan Lieberman45:31

        But you're only gonna eat the food that is available to you. Like breakfast, right? They often don't have breakfast, not because they're trying to intermittent fast and, you know, trying to, you know, skip a meal so that they can, you know, turn off mTOR, et cetera, et cetera. They're, they're doing it because [laughs] there's no food in camp.

    23. RCDr. Rangan Chatterjee45:47

        Yeah.

    24. DLDan Lieberman45:47

        They have to go out and find it.

12. 45:49 – 1:01:36

    Why we struggle to exercise: instincts to conserve energy, plus shame, medicalization, and culture

    1. RCDr. Rangan Chatterjee45:49

       Everybody listening and watching to this right now, Daniel, I'm sure is aware that physical activity is going to be beneficial in some way for them. And as a society, we're trying to move more. Uh, you know, I'm a medical doctor. You know, we're always being told that we should be encouraging our patients to move more and actually to exercise, which potentially is problematic. But it, it's interesting, isn't it, that we're moving less as humans, but we're living longer.

    2. DLDan Lieberman46:22

       Yeah.

    3. RCDr. Rangan Chatterjee46:22

       So what's going on there?

    4. DLDan Lieberman46:23

       Well, I mean, I think it's part of the, the confusion people have, right? We're told that, you know, exercise is medicine and that if you don't exercise you'll get sick. And then they look at people like ... Well, I'll, I'll be very political. They, they look at people like Donald Trump, who, who doesn't exercise, um, and actually believes that exercise is, like, wastes your energy, right? And, um, and they see he's, you know, President of the United States in his 70s, and they wonder what's going on. And, and the answer is that, uh, you know, I think we oversimplify, um, something that is, uh, very important, which is that exercise really does improve your health. Exercise really decreases your chances of getting sick. Um, but on top of that, we have an incredible medical system, as you well know. You're a practicing physician. Um, and we're able to patch people up and keep them going and, and, um, and, you know, treat their diseases and, you know, give them pills to lower their blood pressure and other pills to lower their cholesterol and all the other sequela, the things that result from being physically inactive. And we can keep going. Um, but, but it comes at a cost. And it comes at an increased risk and an increased vulnerability of a wide range of diseases. Just, just, you know, the data are unquestionable. 150 minutes a week of physical activity, just, you know, a brisk walk, uh, can lower your relative risk of dying at a given age by 50%. Um, that's not a, a number I just pulled out of a hat. That's a really, really, really solid number based on, on many, many, many studies. Um, but it, it's not a, it's not a magic bullet. It's not a, you know, guarantee of good health. You could still get cancer. You could still get injured. Um, and, um, and vice versa. So we, we, we need to, you know, be kinda clear about what the benefits are, but also the fact that it's, this is a statistical issue, and it's a complicated issue, and there are no simple solutions to anything.

    5. RCDr. Rangan Chatterjee48:10

       So why is it when the data and the science is really clear that, as you say, 150 minutes of physical activity each week will have multiple benefits ... Or, or let me rephrase that. Uh, may have multiple benefits on your wellbeing and your longevity. Why do so many of us struggle to do that?

    6. DLDan Lieberman48:30

       Because it's, it's, it's abnormal. I mean, it's ... Our instincts-

    7. DLDan Lieberman48:34

       ... are constantly pulling us not to exercise. I mean, our, our instincts are deep and they're powerful. I mean, for, for millions of years, our ancestors struggled to get enough energy to eat, right? They, every day they had to work. They didn't go crazy hard. You know, they didn't, like, work eight hours a day on their feet, you know, you know, struggling to get enough food. They, they ... You know, average hunter-gatherers seemed to work, you know, moderately hard for about two and a half hours a day, two and a quarter hours a day of, of ... You know, and then light, light tasks for the rest of the day. And they, they sit as much as we do, around nine to 10 hours a day. But, but that, that gave them just enough food to survive. Um, you know, there, there are no obese hunter-gatherers, right? And, and if they were to go for, like what I did this morning, go for a, a long run just for the hell of it in the morning, um, they would then waste all that energy, which they could use towards reproduction and the things that natural selection cares about. So nobody in the Stone Age ever went for, for a morning run for the, for the fun of it. And it's, it's a bad idea. And s- and, and, and, and, and whenever you have a chance to save energy, you, you, you should, uh, u- u- until recently. And now we live in this really strange, interesting, modern world, wonderful in all kinds of one- in regards, where we can, you know, spend our entire day without ever getting our heart rate up, you know, press buttons to get food, and shopping carts, and, and, and ... You know, I don't even have to move my hand when I brush my teeth if I didn't want to. You know, I get an electric toothbrush, right? I mean, everything is mechan- mechan- mechanical and, and, and the result is that we no longer have to be physically active, and we now have to do something really weird, which is to, which is to choose to be physically active.

    8. RCDr. Rangan Chatterjee50:06

       [Instrumental music] Now, I'm a huge fan of Vivobarefoot shoes. I've been wearing them for about 12 years now. And one of the main reasons I love them is because when I'm wearing Vivos, I feel fully connected to the ground beneath my feet. What do we want? We want feet that move naturally. And because Vivos are wide, thin, and flexible, your foot can move in the way that it's meant to. A lot of modern shoes are stiff, they're narrow. They start to manipulate the way your foot functions. Whereas in Vivos, your feet can do what they're meant to do, and that means they help your feet become stronger. There was this trial that showed within four months of wearing Vivos, your feet are around 60% stronger. Your feet are your foundation, and when you've got problems in your feet, it goes all the way up the chain. It can go to your ankle, to your knee, to your hip, to your back, and even to your shoulder and neck. And as a doctor, I have seen back pain, hip pain, and knee pain actually start to get better when people start to wear barefoot shoes. To get 20% off your first order, go to vivobarefoot.com/livemore.

    9. DLDan Lieberman51:22

       Uh, and, and although we know up here, right, in our brains that it's good for us, all kinds of instincts just kick in to tell us not to. I think the best evidence for that are when you have, like, a stairway next to an escalator, right? You must see them-

    10. RCDr. Rangan Chatterjee51:35

        Yeah

    11. DLDan Lieberman51:35

        ... you know, there are in tube stops all over the place, and then, you know, s- uh, uh, in airports, everywhere. We all, we all know this phenomenon, right? And, and it doesn't matter where you are in the world. People have studied this in Japan, and in Denmark, and in America, and in Israel and, you know, various places. Wherever there is a stairway next to an escalator, less than 5% of people take the stairway.

    12. RCDr. Rangan Chatterjee51:57

        Wow.

    13. DLDan Lieberman51:57

        And if you put a sign up, that just goes up just a wee bit, right? If you put es- escalators in the Kalahari Desert, you know, they would take the escalator there, too. It's an instinct.

    14. RCDr. Rangan Chatterjee52:06

        Yeah. And I, and I think what you just said there about the Kalahari Desert really [clicks tongue] ... I think it brings it to life for people. Because a lot of people feel bad. They feel guilt. They, they feel shame that they're not moving as much as either their doctor has told them, the, the news has asked them to do, or even people they're following on social media-

    15. DLDan Lieberman52:28

        [laughs]

    16. RCDr. Rangan Chatterjee52:28

        ... who, you know, post a photo, "Hey, just did my, uh, 10K, uh, run before breakfast. How are you all doing today?" You know, that kind of meme, which I think if you, if you find it inspiring and you're like, "Oh, well, man, I didn't do anything. I wanna do that," great. But for many people, they watch that and they're ... And day in, day out, they're feeding their brains with that, thinking, "I'm some kind of failure. Like, look at all these people who can move their body every day and are vibrant and are full of energy, yet just getting through the day is a real struggle." And I think that's one of the beautiful things in your book, is that you, you help people not to feel bad about it. You're sort of arguing that we've not evolved to exercise.

    17. DLDan Lieberman53:11

        Absolutely. We didn't. We're ... Look, we also didn't evolve to go to school, right? I mean, uh, we didn't ... You know, u- until recently, almost nobody read, and nobody ... Nobo- of course, schools didn't exist, right?

    18. RCDr. Rangan Chatterjee53:21

        Mm.

    19. DLDan Lieberman53:21

        I mean, there are so many things of our modern world that are good for us. I mean, no, no parent thinks that sending their kid to school is bad and they shouldn't, you know, learn, that their kids shouldn't learn to read. But, but, you know, that's also a modern abnormal thing. And, and think about how we get school to work, right? We make it compulsory [laughs] . But we also try to make it fun, too, right? You know, we have recess and all kinds of ... You know, you meet your friends there. And we try to make school both fun and necessary, and I think we should treat educ- e- exercise the way we treat education. It, because it's, it's a modern abnormal thing, but it's good for us. And, and, and we should, we should make it necessary, but we should also try to make it fun. But the last thing we should do is make people feel bad about it, because [clears throat] making people feel bad about, about doing what's natural for them, um, doesn't help anybody. And I think the same thing goes with dieting, right?

    20. RCDr. Rangan Chatterjee54:12

        Yeah.

    21. DLDan Lieberman54:12

        I mean, we never evolved to lose weight. Um, but we all ... A lot of people are trying to lose weight, and for good reason, but, but when they fail on their diet, it's not because of some moral failing. It's because there are hundreds of adaptations in their bodies which wanna hold onto that fat, um, and, you know, and, and, and, and elicit a, a kind of a [clears throat] A fast, you know, a, an energetic crisis in their bodies to hold onto that energy, and it's not their fault that they're having a hard time-

    22. RCDr. Rangan Chatterjee54:39

        Yeah

    23. DLDan Lieberman54:39

        ... losing weight. It's, it's the fault of their, their biology, and yet we, we then blame them and make them feel bad. And I think we need to understand that our bodies aren't... We don't just get to decide what we do with our bodies. Our bodies are evolved and, uh, over millions and millions of generations, and we ha- and we need to be compassionate and understand that and work with our biology to find better solutions. I mean-

    24. RCDr. Rangan Chatterjee55:00

        Yeah

    25. DLDan Lieberman55:00

        ... what we've done with exercise is we've medicalized it. But, and I've nothing wrong with the medical profession. Obviously, I, I almost became a, a physician myself, but most doctors' job is to treat people when they're sick, not to prevent them from getting sick, and that's part of the medical system as a whole. That's another issue. But, but the other thing we've done with, with, with, with exercise is we've commercialized it. We've industrialized it. We've commodified it. Uh, you know, tell people to just do it, right? And, and again, there's nothing wrong with medicalizing exercise. There's nothing wrong with commercializing and industrializing exercise. But clearly it's not enough because, like in the United States... I don't know what the data are in England. I've been trying to find good data in England. There's not as much. But, but in the United States, only 20% of Americans actually exercise in their leisure time. That's a really staggering number, right? Um, you know, there are people who are physically active, you know, um, but, but, but not many people actually get out and do it, and there's a reason for that. It's not because they're lazy or, or bad or, or, or, or should feel guilty or ashamed. They're just being normal human beings.

    26. RCDr. Rangan Chatterjee56:01

        Yeah. You know, it, it, it really is wonderful to have someone with your pedigree. You're such an esteemed, highly respected researcher, professor. You're basically saying we need to be kind to ourselves. We need to be compassionate to ourselves. You're making the case with, you know, for physical activity and exercise that we need to be compassionate to ourselves. But I love what you said there about trying to lose weight. We've not evolved to lose weight. And what you just said, what, what you just mentioned there is a sort of central case I've been writing about over the last few months for my next book, which is on weight loss, and I, I very much agree. We have to be kind and compassionate to ourselves and understand we're kind of fighting our biology. You know, the, the environment in which we live is very much re- so removed from the environment in which we've evolved that therefore, you know, we're not doing anything necessarily wrong. We're just doing what humans have always done. Humans have always tried to make things easy, right? We've always looked for high-calorie, energy-dense foods to, so, you know, for as little energy as possible. It just so happens now that on my smartphone I can go on a shopping app and have that delivered to my house without actually moving anywhere. So i- I think it really does help people feel better. I, I read an article with you, Daniel, recently that I think you wrote in the British press, and you said in it that you were the kid who never got picked for the sports team at school. Yet here we are, we're having a conversation, and it's early your time. What is it? 7:30? Quarter to 8:00, something like that?

    27. DLDan Lieberman57:35

        Uh, no, 8:30. It's not that early here.

    28. RCDr. Rangan Chatterjee57:37

        8:30.

    29. DLDan Lieberman57:37

        Yeah.

    30. RCDr. Rangan Chatterjee57:37

        But you've already been for a run. And that made me think about what you've just said about we've gotta make it fun for people. Uh, we've gotta... You know, you, we made school compulsory, but we also try and make it fun, and you're sort of making a similar case for exercise. So is part of the problem also, like with you, and o- o- you've obviously overcome that and you are still, uh, someone who moves regularly, but many people have that experience at school. They're not picked for the teams. They're made to feel, uh, shame and bad about themselves, that they can't be sporty like their friends who have been picked in the team, and that puts them off moving their bodies for life.
13. 1:01:36 – 1:12:15

    Making movement sustainable: fun, social activity, dancing, Parkrun, and commitment contracts

    1. RCDr. Rangan Chatterjee1:01:36

       performance. It doesn't mean that's healthy. It doesn't mean that's what we should all be striving for. And, and I, I think why I find that interesting is because... Have you heard of Parkrun? You familiar with Parkrun?

    2. DLDan Lieberman1:01:49

       Yes, of course. Yeah. No, it's wonderful, Parkrun. Fantastic.

    3. RCDr. Rangan Chatterjee1:01:52

       Yeah, but I, I mean, I'd love to talk about Parkrun at, at some point because there are so many aspects there, community, um, you know, uh, the social aspect to moving together, whether it's run-walk, whether it's walk, whether it's running. Um, but you also get timed at a Parkrun. And I've often wondered, is timing it a good idea or not? Because loads of people who suffer with mental health problems, Parkrun is actually what really, really helps them. That, that strong sense of community. You're moving. You're, even if you're a volunteer at that Parkrun, you still get a lot of benefits. But I wonder then when the timing comes in, and I'm not against it, I'm just sort of posing the question, does that start to make us think about performance and taking us away from just doing it because it's a fun thing to do for some of us?

    4. DLDan Lieberman1:02:46

       Well, I th- yeah. I mean, I think, I think, I think we, you know, there's so many different motivations that people have, and I think we need to, we need to, um, embrace them all, right?

    5. RCDr. Rangan Chatterjee1:02:55

       Yeah.

    6. DLDan Lieberman1:02:55

       For some people, timing is great. It gives them a little impetus. It gets them, gets them, gives them, you know, d- you know, it helps them, you know, do a little better and, you know-

    7. RCDr. Rangan Chatterjee1:03:04

       Yeah

    8. DLDan Lieberman1:03:04

       ... challenge themselves. Other people find it defeating and then, and, and, and, and, and off-putting. And, and so I think, you know, we should let a thousand kinds of physical activity bloom, right? And if, and if, and if, you know, Pa- you know, there's never gonna be one type, right?

    9. RCDr. Rangan Chatterjee1:03:18

       Yeah.

    10. DLDan Lieberman1:03:18

        For some people, why not just dancing? I mean, I, well, I have a section in the book on dancing, which is-

    11. RCDr. Rangan Chatterjee1:03:23

        You do, and I've got that written down to talk to you about 'cause-

    12. DLDan Lieberman1:03:25

        Yeah

    13. RCDr. Rangan Chatterjee1:03:25

        ... I didn't know that at all. So please-

    14. DLDan Lieberman1:03:27

        Yeah

    15. RCDr. Rangan Chatterjee1:03:27

        ... do expand on that.

    16. DLDan Lieberman1:03:28

        Yeah.

    17. RCDr. Rangan Chatterjee1:03:28

        It was a brilliant section.

    18. DLDan Lieberman1:03:30

        Yeah, I mean, every culture in the world, I, I can't find an exam- an exception, has, has not only just dancing but endurance dancing as part of its, as part of its culture, you know? People, people dance for hours, um, in, just, just about every culture. And I even, y- even in Jane Austen, I found some wonderful quotes in Jane Austen in, you know, Georgian England where people, you know, dance the night away, right? Um, um, it's, it's, it's a way of making physical activity... And they probably didn't think of it as exercise. It was social. It was fun. So there are many, many ways for us to get our bodies moving and to, and, and to, and get the benefits, the, the mental health benefits, the physical health benefits. And I think we should, if we're gonna be successful, we need to try to, you know, we n- there's not, not gonna be a one-size-fits-all approach, right? There's gonna have to be many approaches. I mean, look, there are some people, I, yeah, as you, as you know 'cause you read the book, throughout the book I make fun of treadmills because treadmills are, you know, for me, the apotheosis of exercise. Here's a machine. You know, you have to spend money to buy it or spend money to go to the gym to use it. It makes you work hard to basically stay in the same place. You get nothing done. It's loud. It's noisy. You know, it's, the air is fed in. I mean, I, you know, I, I put people on treadmills for a living, but I hate treadmills. I mean, I have one in my basement, and I sometimes use it. So what some people do is they, they, you know, they listen to a podcast or maybe, maybe this podcast or, or they'll watch a movie or, or, or whatever to tolerate the treadmill. And, you know, if that, if that works for them, that's great. There's nothing wrong with that if... It's actually very efficient. You can do two things at once. You can listen to a podcast and get some fit- exercise at the same time. But, but others just can't stand it. So let's, let's not be judgmental. Let's, any, any way that works is, is great. I mean, and we just have to support them all.

    19. RCDr. Rangan Chatterjee1:05:12

        I'm a big fan of individualized and personalized approaches, and I really like that idea that maybe we've gotta broaden out what we recommend s- to people. Say, you know, it doesn't matter, um, how you move your body, but you just wanna move it more, um, and find what actually works for you. But are there any sort of universal principles when it comes to movement that actually do work for all of us?

    20. DLDan Lieberman1:05:40

        In terms of getting us to move? I mean, I, again, I go back to the simple... I mean, my, my, you know, I think there's two, again, two basic impetuses that have, you know, over, over millennia have been the basis for w- how and why people move. And one is it, because it's necessary, and the other is because it's fun. And for most people, fun involves social. Um, um, so, uh, sometimes, you know, sometimes going for a run by yourself or a walk by yourself is meditative, and it's nice to be by yourself, and you can think through a problem. But for most of us, you know, we like to be with other people, and so s- that's why Parkrun is so successful. It's social. Here in Cambridge, we have the November Project. Every Wednesday people do these wonderful runs, and they run up the stadium, and they do all kinds of great stuff.

    21. RCDr. Rangan Chatterjee1:06:25

        Wow.

    22. DLDan Lieberman1:06:26

        We have, you know, all around the world there are various kinds of, of, of social events. There are... You know, dancing is social. Um, uh, playing a game of, you know, soccer or football is social. I mean, the list goes on, right? Um, and, um, and there are many ways to do it socially, and I think, so, so that's critical. Um, but, but that's never gonna be enough for some folks. And, and, and, you know, exercise, physical activity used to be necessary in our lives, and that was the impetus that people had to get out and, uh, you know, every day and, and do work. And so we need to find ways, without coercing them-... un- un- unethically, uh, to make exercise, to make physical activity necessary. And, and because it's not appropriate to tell adults that they, you can't, they can't have the benefits of society unless they exercise, right? Um, we, we need to help people help, help themselves, and I think the way to do that is through what's called a commitment contract. So let me go again back to education. In education, we ha- education works on a commitment contract basis for adults, right? So I'm a professor in a university where people pay ghastly sums to go to Harvard, right? I mean, I think the tuition is, and, and, and room and board and all that costs like 60 to $70,000 a year. That's full, full. Of course, most students don't end up paying that. I mean, the vast majority get financial aid. So, so [laughs] don't worry, most of my students are not fabulously wealthy. Actually, many of them are first-generation students, 'cause we have... We're lucky, we have really good financial aid. But anyway, somebody's paying 60 to $70,000 every year for them to go to school, and there's some commitment from them to go to school. And, and w- and what are they doing? They're having people like me torture them, right? I make them take exams, I make them read books, I make them stay up late at night studying, and if they don't do well, I give them a bad grade, which, you know, which, you know, stigmatizes them for the rest of their life. And, and, and, um, but they do it willingly because, because they've signed a kind of a commitment contract, whereas, whereas they're paying money for me to make them do stuff which they know is good for them, which they wouldn't, otherwise wouldn't do for themselves. And we do all kinds of other commitment contracts in our, in our, in our world, and, and I think exercise is, should be part of that. We should, we should find exercise... You know, there are many w- so there's a wonderful program called stickk.com. It's a website run through, uh, some economists. They used to be at Yale. I'm not sure if they're still at Yale. Where you can basically pick either a stick, carrot or a stick, right? And, and I describe this in the book 'cause it-

    23. RCDr. Rangan Chatterjee1:08:50

        Yeah, you do, yeah

    24. DLDan Lieberman1:08:50

        ... a funny article about this. 'Cause there's a friend of mine in, in San Francisco who was, who has been trying to lose weight, and she, uh, gave stickk.com, I think, $2,000. So not an un- not a small amount of money. And every week she agreed that she was gonna walk a certain number of miles, and if she didn't get those number- miles in, and her husband was her referee, if she didn't do those miles as affirmed by her husband, they would automatically send $50 that week to the National Rifle Association.

    25. RCDr. Rangan Chatterjee1:09:19

        [laughs]

    26. DLDan Lieberman1:09:19

        That's the big association that tries to prevent, uh, gun control laws in the United States. And she is very, very much hates the NRA and wants to see gun, gun... And she has never missed a week of her walking since she's been doing that. So she, she signed a commitment contract, put some money behind it. Now, that's a kind of an extreme one, but there are other ways we can do it, just with, through a friend. I mean, a lot of the, my early morning runs, I don't... You know, at 6:00 AM, I do not wanna run, I promise you. I mean, nobody-- I wanna be in bed with my wife, right? But I often meet a friend of mine, uh, who's a cardiologist, and he's up at 6:00 AM, and he doesn't wanna be there either. But we kind of agreed the day before that we were gonna meet each other at 6:00 AM, uh, to go for a run, and, uh, usually we're just, like, irritated at each other, and we don't even speak for the first, you know, 10 minutes. Um, and then slowly we warm up, and I'm never unhappy that I did that run at the end, but I, I, I did it because I f- I coerced myself through a commitment contract.

    27. RCDr. Rangan Chatterjee1:10:14

        Yeah. V- v- very, very practical and pragmatic approach. I guess what you're saying is that the way we've typically encouraged physical activity has been, you know, very prescriptive. You have to do this. Um, you know, if you don't do it, you're not really looking after yourself. You sort of have to rely... We, we, we're very much putting it down to individual motivation, individual willpower, and what you're saying, I, I guess, is that this is not working, right? We've not evolved to exercise. We, we're, we're now living in a society where we simply don't have to anymore. That necessity has gone. So you need to find a way to make it necessary, and the way you've found of doing it is you're meeting someone. So if your buddy has gone to the trouble of getting up early in the morning and goes to your agreed spot, and you don't show up, there is a bit of... You know, you have social pressure to show up, which is why so many movement programs talk about, you know, doing it with other people, right? Because if you're leaving it up to yourself to motivate yourself, there's gonna be times... Like, I know when I got into Parkrun, I remember thinking, at the time I wasn't really a runner, right? And we can, we can, uh... Let, let, let me put it another way. I didn't perceive myself as a runner, whereas now I do. But I still went because I did it with my son, uh, is, is reason one, and reason two is there was this big community there, this really friendly community at Parkrun. So I just had to make sure that my son and I were at the start line by 5 to 9 on a Saturday morning, and if that was... If, if I got there, I would complete a 5K. But if I had to do that myself, even if I had to do that s- myself with my son, I bet you some Saturdays we wouldn't do it. And so I think that accountability piece is, is... I think it's really interesting. Now, y- you mentioned you're

14. 1:12:15 – 1:52:55

    Coercion and workplace culture: the Björn Borg ‘sports hour’ experiment and modern ethics

    1. RCDr. Rangan Chatterjee1:12:15

       not a fan of coercion, yet you write, uh, a very surprising, certainly surprising to me, you write about, is it the Swedish, uh, is it Björn Borg?

    2. DLDan Lieberman1:12:26

       [laughs]

    3. RCDr. Rangan Chatterjee1:12:27

       The, the Swedish underwear, sportswear manufacturer.

    4. DLDan Lieberman1:12:30

       Yeah.

    5. RCDr. Rangan Chatterjee1:12:30

       And I was mesmerized reading that story. So I wondered if you could tell that, and because that's actually taking a quite different approach, right?

    6. DLDan Lieberman1:12:37

       Yeah. I had so much fun doing that. So I, I was in, I was thinking about this, you know, 'cause I... The last section of the book, the last quarter of the book is really about how to apply the sort of natural history of exercise to the modern world, and I was interested in this idea of coercion, and I wanted to see if I could find an example of people who are forced to exercise, adults. I mean, we force kids to exercise in school, but nobody, nobody blinks an eye at that 'cause we force kids to do all kinds of stuff and think it's totally acceptable, 'cause children can't make up their own-You know, children aren't responsible for their own decisions, but adults are. And I, so I was, I was searching throughout the world. I was looking, I was thinking about, like, monks in Asia who are forced to do things and whatever, and I was... I wanted to... You know, I'm very into participant observation. I like to try what I study. And so, you know, that's why I've tried barefoot running and the... I've, you know, I try to, I try to... That's why I've chased animals on, you know, done, done races against horses and, you know, I'm, I'm into that. I like, I like

    7. RCDr. Rangan Chatterjee1:13:27

       W- we're, we're gonna come to all that, believe you me. [laughs]

    8. DLDan Lieberman1:13:29

       Yeah. I like to put myself in the shoes of the, or the, uh, of the, of the, of the, the people I'm studying. And, um, and so I, I found on the web a few articles about the Björn Borg company. It's a company in Sweden that makes, uh, mostly underwear, but other kinds of sports clothing. Um, it's no long- actually no longer owned by Björn Borg, but it's, um, uh... And, and, you know, it's... You know how those p- companies have those, like, little contact me thing? So I, you know, late at night, I, I remember telling my wife I'd found this company and I'd read some articles, and she, she said, "Well, contact them." So I, I, I, I got on the contact page and I said, you know, "Dear Björn Borg company, I'm a, I'm a professor at, you know, whatever. I'm interested in this topic and I'm kind of curious to learn more." And I remember going to bed and saying to her, "Yeah, I'm sure I'll never hear from them." And then the next morning in my in- inbox was an email saying, "Come and, come and join sports hour. [laughs] Come any time you want. We'll, we'd be happy to show you." [laughs] So I, uh, so I was on sabbatical and I had some time, so I got on an airplane and I went to, to, you know... Uh, they were very kind and they told me when to show up. So I, I, um, I showed up and they basically said I could talk to anybody in the company and, you know, I had to go to sports hour 'cause at Björn Borg company, everybody has to exercise. It's, it's, it, there's, it's a requirement. And e- there's a sports hour o- every Friday at, I think it's 10:00 AM. And, and there's no excuses, unless, unless you're injured or whatever, uh, or something like that. If you're a board member, if you're a visitor, it doesn't matter who you are. If you sweep the floors, if you're the CEO, doesn't matter. You go to sports hour. And so I, I went to sports hour, which is a really hard kind of CrossFit workout. Uh, it was great. It was exhilarating. And you, you can do it as hard as you want or as light as you want. Um, and, um, and then they have all kinds of other events where they, you know, instead of a Christmas party where everybody gets drunk, they run through the streets of Stockholm and have hot chocolate afterwards, you know? I mean, it's a, it's a delightful environment. But of course, you know, not everybody liked it and some people left the company, but some people who are in the company love it. And I just talked to folks about it and see, to see how it worked, and to my surprise, it was a, it was actually pretty popular. Um, and, um, uh, the people actually kind of realized that it was a beneficial thing. But I should also say these are people who've drunk the Kool-Aid, as we say in the United States, right? The, you know, everybody who really hated it has obviously left the company, you know? You wouldn't b- be in that company if you didn't think this was acceptable. But, um, but you know, the fact of the matter is that's, as far as I can tell, the only company in the world that does that, and we're not gonna find... You know, that's just not gonna work in most places, and we have to find other ways, uh, to make exercise necessary.

    9. RCDr. Rangan Chatterjee1:16:05

       Yeah, what, what's interesting about that company for me, uh, and, you know, y- you're absolutely right. There is, there's that inbuilt bias, isn't there? Because people, I guess some people, if they know that about the company and that's not their kind of thing, they may not even apply for a job in the first place. If they start working there and they think this is a good idea, but then they feel it's too much pressure, there's, you know, there, there's some sort of camar- camaraderie that they don't like or they don't thrive on, they might leave. Um, but it's an interesting model, and I appreciate this cannot be rolled out across society. There's a kind of ethical point there, I think, as well. But you know, I, I wonder what you think about the ethics of that, where a company says, "Hey, look, we..." A- and again, I'm, I'm not speaking for that company 'cause I don't know the, the ideology behind it, but let's say a company felt that, well, we know physical activity is imp- is important because it will help the employees, it will help them with their health and wellbeing. It's gonna help them concentrate, focus, be more productive. It's a great way of bonding. Um, you know, w- I, I guess what, what would happen if companies started to... Some companies were like, "Well, look, this is part of the culture here, and if you wanna work here, this is sort of what we would be supporting." It's, it's quite a tricky one ethically, isn't it? Because it could be done in a way where it's very supportive and it's like, well, if you just wanna walk for that hour round the gym, that's fine. You know, there's gonna be no pressure on you from your manager or from the boss. You know, I know, I know it, it... You'd, you'd have to demonstrate that there was no discrimination by doing that. But it, it's working there. I mean, could that be a, could that be a s- you know, you're saying that we need to take personalized approaches.

    10. DLDan Lieberman1:17:56

        Well-

    11. RCDr. Rangan Chatterjee1:17:56

        So could that work for some companies?

    12. DLDan Lieberman1:17:58

        Well, I mean, let's, um, let's, uh, let's rev- let's flip the question and ask did that used to work for some companies? So, so in the United States, um, as in e- every, every, you know, in, in Europe, um, universities are kind of like companies, and every university until recently required students to exercise. Uh, in the United States, physical activity, physical education was 100%, you know, every single university in the country, Harvard included, required physical education.

    13. RCDr. Rangan Chatterjee1:18:23

        Wow.

    14. DLDan Lieberman1:18:23

        Um, and, and, you know, going back to, to the ancient, you know, Greek philosophers and in, you know, the traditions in India and China, everywhere in the world where you had educational systems, which of course were for elite people, right? 'Cause, uh, peasants didn't go to, go to school, but, but n- but wealthy aristocrats did. With no exception, educa- uh, exercise became part of people's education because people n- understood that there was a relationship between exercise and, you know, phys- the body and the mind, right? Mental health and physical health, and that exercise is good for students. And, um, that was dropped in the United States in, starting in basically in the '70s. So Harvard, for example, got rid of its physical education requirement in the 1970s. Um, and now, you know, we kn- we see the, we see the results. But these are adults, you know? These are 18-plus-year-old people, and it was required. And, um-Um, so, you know, I think this... And, of course, until recently everybody had to be physically active to get to work. They had to, you know, walk to get to work. They, they didn't have elevators to get them to their floor. You know, I mean, we could go on with all the things that have changed in the world. So we've kind of shifted our, our, our, our workplace and shifted our, our schools without shifting, uh, the, the, the, the kind of how we approach our bodies. And so maybe Björn Borg Company is going back to something very ancient in a new way. Um, but, um, but, you know, we, the fact that we're so uncomfortable with it, I think is interesting. Um, we're, we're, we're just so worried about, about, about, about coercion and people's rights and, and for good reason. Um, but we're also, um... I think, I think sometimes w- we, you know, we also... I'm gonna probably get myself in trouble now. Um, but look, I think it's... As you can probably tell, I'm very opposed to body shaming and fitness shaming, right?

    15. RCDr. Rangan Chatterjee1:20:13

        Yeah.

    16. DLDan Lieberman1:20:13

        It's, it's, it's unacceptable. Um, but sometimes I think because we're so worried about body shaming and fitness shaming, we, we go, we go s- to the extreme and basically turn off the whole system.

    17. RCDr. Rangan Chatterjee1:20:26

        Yeah.

    18. DLDan Lieberman1:20:27

        And, and I wonder if the, if, if we can't have our cake and eat it too, so to speak, right? Can we find a way to help people be physically active without engaging in body shaming, without engaging in fitness shaming? And I think we can. And again, I'm gonna go back to my commitment contract model because if... Let's just say you're, you're unfit, you're overweight, you're struggling, you hate to exercise, but you wanna, you wanna get... You wanna exercise. Now, if I told you I had... You had to go to a CrossFit, you know, workout every week and, you know, do 150 burpees with a, with this, you know, highly muscled, you know, you know, nutcase in front of you who's your boss, you'd, you'd hate it, right? But if you could just walk 20 minutes a day, climb the stairs, right? Pick your own goal and work towards that, you know, that would fit your, your fitness level, your, your, your, your... You know, you could do it, uh, on your own, you could do it with friends, et cetera. Not in a way that it's, you know... We can find ways for people to be more physically active that can, can accommodate every disability, can accommodate every level of fitness, can accommodate-

    19. RCDr. Rangan Chatterjee1:21:32

        Yeah

    20. DLDan Lieberman1:21:32

        ... you know. But, but we, we, as a society, we've been very uncreative about it. We're, we're, we're, um, we're not really willing to put in the time and the money and the effort to make it happen.

    21. RCDr. Rangan Chatterjee1:21:43

        Exercise is something that 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.

    22. DLDan Lieberman1:21:56

        Oh, I would say we didn't evolve to do it at all. But yeah, that paradox is what really motivated my last book, Exercised. And maybe to answer your question, I'll give an anecdote, right? Which is, um, I use in the book. But, uh, I was just finishing up a previous book, The Story of the Human Body, and I was in Mexico doing some research. And we were studying, you know, 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, uh, 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, and I had asked all kinds of other people the s- exact same questions with a translator. And one of the questions was about training, and everybody had always struggled with this question because, uh... And, you know, I was beginning to realize that my concept of training was kind of alien to, um, to the Tarahumara. And this guy just looked at me, and I could tell without even the translator saying anything, he's like, "Why would anybody run if they didn't have to?" And I suddenly had this, like, bzz, you know, this little epiphany, right? That, uh, that our concept of exercise is alien to most people, right? And of course, I work in parts of the world where, where people are very physically active. They work hard. Here, here I was in a part of the world where people are h- hardworking farmers, they've got no machines-

    23. RCDr. Rangan Chatterjee1:23:13

        Mm-hmm

    24. DLDan Lieberman1:23:13

        ... 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. Um, but the idea of going for a five-mile run in the morning is nuts. Nobody does that. Um, so I think... And, and, and I had this sudden, like, bzz, this moment that, yes, we evolved to be physically active, but the kind of what we call exercise, which I define as voluntary, discretional 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, a farmer or a hunter gatherer, of course, we were hunter gatherers for mot- most of our existence. If you're struggling-

    25. RCDr. Rangan Chatterjee1:23:52

        Mm

    26. DLDan Lieberman1:23:52

        ... to get enough energy, right? Struggling to feed your family, going for a, a five-mile run in the morning, which is about 500 calories, is a terrible idea, right?

    27. RCDr. Rangan Chatterjee1:24:02

        Yeah.

    28. DLDan Lieberman1:24:02

        Because you... Those 500 calories are, is energy that you could use either on your own body or on, on your, your family, right? So, so, so the idea of doing unnecessary voluntary-

    29. RCDr. Rangan Chatterjee1:24:15

        Yeah

    30. DLDan Lieberman1:24:15

        ... physical activity for no reason other than for your health and fitness when you're already very physically active is nuts. So, 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. Um, work is, is rewarding. Um, 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, get, getting absolutely nowhere, there's a reason people dislike it. We, we never evolved to do that.
15. 1:52:55 – 2:10:35

    Minimalist footwear and foot strength: what shoes protect, what they weaken, and why calluses matter

    1. RCDr. Rangan Chatterjee1:52:55

       You mentioned footwear then. Um, you're probably regarded, I think, as one of the, the godfathers of the minimalist-

    2. DLDan Lieberman1:53:03

       [laughs]

    3. RCDr. Rangan Chatterjee1:53:04

       ... shoe movement. I don't-

    4. DLDan Lieberman1:53:05

       I'm the, the barefoot professor. Yeah. [laughs]

    5. RCDr. Rangan Chatterjee1:53:06

       Yeah. I don't know how that, how that ha- uh, sits with you.

    6. DLDan Lieberman1:53:10

       [laughs]

    7. RCDr. Rangan Chatterjee1:53:10

       But, um, let, let's go there. You know, you, you, you do mention it quite a bit in Exercise as well about the footwear that these less industrialized populations routinely wear. Um, you know, many things in life have got ... There, there are trade-offs. There's pros and there's cons. Um, what are some of the benefits, do you think, of those populations and potentially us wearing, um, kind of less cushioned shoes or, or for want of a better term, minimalist shoes?

    8. DLDan Lieberman1:53:43

       Uh, well, I think the word that you used, trade-offs, is the operative word, right? There are benefits and costs to everything.

    9. RCDr. Rangan Chatterjee1:53:51

       Mm.

    10. DLDan Lieberman1:53:51

        Just about everything on the planet.

    11. RCDr. Rangan Chatterjee1:53:52

        Yeah.

    12. DLDan Lieberman1:53:52

        There, there might be a few exceptions, but they're hard to think of, and shoes are one of them, right? So shoes, the big benefit of shoes, apart from the fact that they can look sexy or nice or all that kind of stuff, is that they protect your foot, right?

    13. RCDr. Rangan Chatterjee1:54:03

        Yeah.

    14. DLDan Lieberman1:54:03

        They protect the sole of your foot from damage. And the, and the other thing that we look for in shoes today in, in, in high industrial, you know, wealthy populations, is for comfort. So we wear shoes because they're, they look good, they protect our feet, and they're comfortable. But the trade-off is that, um, that, uh, is really the most important trade-off is that they make our feet weak. So what a shoe does is it kind of does some of the work for you that the muscles in your foot would otherwise do. If you have a shoe that has a ... Like if you've ever gone for a walk on the beach, which I'm sure you have, or gone for a run on the beach, after a, a day of running or walking on the beach, your feet are kind of tired. Why is that? Because when you're pushing off from the, from the sand of the beach, that's a, that's a compliant surface, and now you have to, you have to use your foot muscles have to work harder to generate force.

    15. RCDr. Rangan Chatterjee1:54:52

        Are you talking about walking on the beach without shoes on?

    16. DLDan Lieberman1:54:54

        Without, barefoot.

    17. RCDr. Rangan Chatterjee1:54:55

        Yeah.

    18. DLDan Lieberman1:54:55

        Thank you. But if you were to wear shoes, it's a lot easier because you've now made the, the surface now stiff, and so you can push ha- You, we have this old expression in America, you can't fire a cannon from a canoe, right? Right? Um, if you push off from a stiff shoe-

    19. RCDr. Rangan Chatterjee1:55:09

        Yeah

    20. DLDan Lieberman1:55:09

        ... right, you're now, your foot muscles have to do less work.

    21. RCDr. Rangan Chatterjee1:55:12

        Yeah.

    22. DLDan Lieberman1:55:12

        And your muscles in your feet are like the muscles in any other part of your body. If you use them more, they, they're stronger, and they-

    23. RCDr. Rangan Chatterjee1:55:17

        Mm

    24. DLDan Lieberman1:55:17

        ... they're larger. And so by having shoes that are stiff but also having arch supports in them and toe springs and all the fancy schmancy features that we have in our shoes enable our, our, the foot muscles in our feet to atrophy, um, or not grow to the extent that they normally would have grown-

    25. RCDr. Rangan Chatterjee1:55:34

        Yeah

    26. DLDan Lieberman1:55:35

        ... and, and be as strong. So we've published studies where we've, we've a- we've taken out into the field, um, just an ultrasound, you know. Now we can ... These really cheap ultrasounds that work on a tablet. It's amazing the technology.

    27. RCDr. Rangan Chatterjee1:55:46

        Yeah.

    28. DLDan Lieberman1:55:46

        So we can go out and ultrasound people's feet in, in, in Kenya and places like that, in Mexico, and people who don't wear shoes have much stronger foot muscles. That's the best way to measure foot strength is the s- cross-sectional area of the muscles. And we can look at people from the same population who live in the city who wear shoes all the time, and they have-... smaller, weaker feet. They also have a much higher percentage of, of flat feet.

    29. RCDr. Rangan Chatterjee1:56:09

        Mm.

    30. DLDan Lieberman1:56:09

        Um, so actually out in the, in the areas where people are habitually barefoot, we don't see flat feet at all. I mean-

Episode duration: 2:10:35