- Treadmills are really weird. They're a strange,
modern piece of equipment that we spend a lot of money on, and we spend a lot of
money to go to a gym- that makes you work really
hard to stay in the same place. 'It's the apotheosis of exercise.' Think about it a treadmill, right? We think treadmills are
synonymous with exercise, but it's a noisy, expensive machine that makes you work really,
really hard for no purpose other than to make you move
without getting anywhere. Most of us, if we're forced
to be on a treadmill, we listen to a podcast or some music, we watch something on
our iPhones or whatever to make it tolerable. My name is Dan Lieberman. I'm a Professor of Human
Evolutionary Biology at Harvard University, and
I'm the author of "Exercised," why something we never evolved to do is healthy and rewarding. The very first treadmills
were probably invented by the Romans or even some
other ancient peoples like that to move wheels and stuff like that. But the modern treadmill's real genesis comes from Victorian prisons. They were invented by a
man named William Cubitt at some point in the 19th century to prevent prisoners in
England, like debtors' prisons, from relaxing and enjoying themselves. So they would make prisoners
sort of trudge for hours a day on these big slat-like treadmills to make it unpleasant
for them to be in jail. And of course now, people
still trudge on treadmills, except they do it on their own volition, but many of them still feel like it's a kind of form of torture. I don't know anybody who really
enjoys being on a treadmill. - 'It's easy to squeeze your way to shapely hips and thighs.' - So many modern forms of
exercise are kind of like cod liver oil-they're not really pleasant. - 'Extra sunshine for us
in winter and spring.' - We do them because they're good for us. - 'Come on, go, go!' - But it's not fun. - 'Make your muscles cry.' - And so it's like taking your medicine. It's important to make a distinction between physical activity and exercise- so physical activity's just moving. You do anything: go shop, pick up your groceries and take them to your car,
that's physical activity. When you sweep the kitchen
floor, that's physical activity. But exercise is discretionary,
voluntary physical activity for the sake of health and fitness. The word exercise comes from
the Latin 'exercitatio,' and it meant "to train." We still do math exercises. When you were plowing
a field, for example, that would be considered exercise
in sort of early English. Or soldiers do exercises to get fit. On the other hand, it also
means to be exercised, to be upset, to be
confused, to be anxious, to be kind of worried. You know, we get exercised
by our math exercises. In the modern world, a lot of people are confused about exercise. They find it hard to do,
they're not quite sure how much to do, there are all
kinds of myths surrounding it. - 'The burning is a
signal that your muscles are working harder than they should.' - Most people don't do
it because they want to, they do it because it
helps to stave off death and decrepitude. By shining the light of evolution and using kind of an
anthropological perspective, my goal really is to help
people be less exercised about exercise. - 'Right, left, right, left. Walking is one of the great exercises for people of all ages.' - If there's any one physical activity that humans evolved to do, it's to walk. Walking is the way which
humans get around, get food. It's kind of fundamental
to who are as a species. Today, in the modern
Western world, with cars and escalators and
elevators and Zoom and TV and all that sort of stuff- we just don't walk very much. You know, the average hunter-gatherer will take maybe 10-15,000 steps a day. The average American, before the pandemic, was taking something like 4,700
and something steps a day. So a lot less than our ancestors. One of the ways which
we medicalize exercise in the Western world is that we think there's a certain amount
you should do, right? We prescribe it. "You should take two aspirin,
you should get eight hours of sleep, and you should
walk 10,000 steps a day." We like that, right? There's nothing necessarily
wrong with a goal, right? Goals can be really helpful, actually. But 10,000 steps is kind of arbitrary. The number actually came
from when the first pedometer was invented in Japan
before the 1960s Olympics. In the board room, they
were trying to decide what to call it. It turns out that 10,000
is a very auspicious number in Japan, and they thought
it kind of sounded good, it seemed kind of reasonable, so they called it 10,000-step monitor- and that kind of stuck. Surprisingly, it turns
out that 10,000 steps isn't actually a bad goal. If you actually look at what people in non-Western societies do, 10,000 steps isn't actually that far off. So, it's a perfectly
reasonable goal to shoot for, but there's nothing,
like, special about it. If you do 8,000 steps, that's fine; if you do 15,000 steps, that's fine. The important thing is
to be physically active because some is better than none, and a little bit more tends
to be better than that. But you know, it's all good. There's no magical number. It's not a U-shaped curve
with a bottom on it, right, where it tells you what
you should aim for. That does not exist. I mean, every culture
engages in sports, right? It's a human universal. Sports are important. They serve all kinds of functions. There's a lot of wonderful
things about being on a team and especially when you're children, you learn good sportsmanship. If somebody scores a goal on you, it's not appropriate to
bash them in the face, that sort of thing. You learn hierarchies,
you learn companionship, you learn how to cooperate. But some sports also have another origin. It's not coincidental
that a lot of the sports, for example, in the ancient
Olympics, especially, were skills that were really
important for warriors. You know, javelin throwing
and chariot racing. Well, we don't do chariot racing anymore. Sprinting, wrestling, boxing, right? These are all very kind of
physically demanding sports that are kind of combat-related. Sports, I think, evolved also to help us learn not to be 'reactively aggressive'- sort of like an instant kind
of non-planned aggression. I mean, the extreme to me is tennis. - 'You cannot be serious!' - You're not even allowed to swear when you're playing tennis. - 'We're not gonna have a point taken away because this guy is an incompetent fool. You know that? That's what he is.' - Road rage is a perfect
example of reactive aggression. - 'I'm walking here, I'm walking here. Up yours, you screwball!' - But there's also 'proactive aggression,' when you plan something, premeditate, you work it out in advance. War is an example of a
proactive aggression. Sports are also kind of
proactive aggressions sometimes. It's perfectly acceptable to appropriately proactively aggressive, as long
as you're within the rules. And that's what humans excel at. We're better than most species at curbing reactive aggression,
though not so often, but we are capable of
extraordinary proactive aggression. You know, every once in a
while there's a mass shooting, and there's a kind of standard reaction. Everyone says, "Oh my gosh,
how could this person do this? I go to church with him, and whatever. Just a nice person, etc." But we're confusing reactive aggression with proactive aggression. Hitler was a vegetarian, but of course one of the most proactively
aggressive human beings who's ever lived. We shouldn't confuse these two different kinds of aggression. Our bodies weren't designed,
they weren't engineered, they're not machines- they evolved. And so if you want to
understand why our brains work the way they do, why our
feet work the way they do, why we run, why our immune
systems function the way they do, the only explanation for
those types of questions is an evolutionary question. There's an old expression: "Nothing in biology makes sense except in the light of evolution." I would say that nothing
about human behavior makes sense except in the light
of culture and anthropology, and we need to understand
the cultural component to our behaviors as well.
