BORN TO BE LAZY?
Anthropologist Daniel Lieberman explains why training for fun is counter to human instinct – and how to overcome it
If your motivation to exercise has been faltering lately, evolutionary biologist Daniel Lieberman sympathises. He argues that recreational training runs counter to human instinct, and that our ancestors weren’t as fit as the popular myth suggests. Could it be that you were born to be lazy?
f exercise is integral to our health and longevity, why do many of us find it so uncomfortable? If this thought has ever crossed your mind, Daniel Lieberman’s Exercised is the eye-opening, mind-expanding and potentially body-reshaping book for you. Lieberman is a professor at Harvard and a keen marathoner – sometimes barefoot. His life’s work in evolutionary biology makes him your ideal companion for a journey through the history of exercise, rest and health. And he can explain why a desk job might not be as bad for you as you think.
A theme of your book is that there’s too much conflicting information about what constitutes “good” exercise. With so much research into it, why are we still so confused?
That’s a good question. First, we tend to oversimplify things. People like to give and receive simple answers, because they don’t want complexity. Second, the problem with biology is that it’s a messy topic. Bodies are messy and, if you try to oversimplify, you’re going to get it wrong. But we have, in many ways, medicalised and industrialised exercise. And in order to do that, you need to have a simple message.
But haven’t you tried to distil tens of thousands of years of human evolution into about 300 pages?
I still needed a book to do it! You couldn’t do it in a pamphlet, right?
Sure, but you do make a snappy conclusion to summarise your work.
Yes: make exercise necessary and fun. Do mostly cardio, but some weights. Some exercise is better than none. And keep it up as you age.
You’ve been criticised for writing another self-help book, even though you’ve explicitly stated that this isn’t one. What was your objective for it?
Well, hopefully, by the end of this book, you’ll better understand what you’re doing and why. Of course, many people are already into exercise and they know all this. But I wanted to write a book that was equally interesting and useful for people who feel confused about exercise and feel shamed, blamed or even bullied. They are the vast majority of the world, and they have a lot of questions.
What surprised you in the research and writing of this book?
I wasn’t planning to write about rest and inactivity. But to write about physical activity, I needed to write about the other side of the coin. I was as surprised as anyone when I read the literature on sleep, because I always thought that you needed eight hours of sleep. You don’t. And I was very surprised to read just how hyperbolic a lot of the arguments about sitting are. The evidence suggests that the sitting position doesn’t really have any effect on your back. There’s a tonne of data on that. Hundreds of papers. I emailed the guy in Ireland who is the world’s expert. He told me, “Yeah, I’ve written, like, 20 papers on this and nobody, nobody,
pays any attention.”
So, are you saying that we can slouch in any old chair and that’s OK?
What’s associated with poor health outcomes is leisure-time sitting. If you’re sitting all day at work, then you come home and sit, you’re not getting any physical activity. Interrupted sitting is really important. Huntergatherers evolved to sit in a periodic way, to get up to run after a child, or tend the fire. Now, we can sit for hours watching a movie, staring at a computer screen, or whatever. That kind of uninterrupted sitting has negative metabolic consequences.
Is our behaviour counter-evolutionary, in that the majority of us aren’t doing what our bodies are designed to do?
My previous book, The Story of the Human Body, dealt with that: why our bodies are not necessarily adapted for the kinds of environments in which we now live, and that explains why we get so many diseases like heart disease, cancer and diabetes. This book’s a sequel. It’s about how exercise fits into that.
But haven’t humans sort of recognised that? We invented jogging, gyms and fitness trackers to fight it.
That’s evolutionary, isn’t it?
It’s a cultural evolution. The problem is that we tell people that if they don’t exercise, there’s something wrong with them. But it’s not a natural instinct. We have to choose to do it. When I go to my office, which is on the fifth floor of a Victorian building on the Harvard campus, I guarantee you that, every single time, I want to take the elevator. It’s my instinct, right? The reason I don’t do it is that if anybody catches me, they’ll label me a hypocrite.
You’re a keen runner, so surely you’ve earned the right to take the lift? Isn’t the point here to reach the people who don’t ever take the stairs because it’s too hard for them?
We have to understand that all of us struggle with these instincts. You might think that I’ve earned the right not to take stairs, but I’m still better off if I take them rather than the elevator, even if I went for a five-mile run in the morning. It’s normal to want to be physically inactive, and we now have to make choices that we never evolved to make. And that’s hard.
Do you still run barefoot?
Most of the time, I wear shoes. I occasionally enjoy taking them off. I did a good run this morning: I did the virtual
Boston Marathon. Running is keeping me sane right now, during COVID-19.
Another thing that’s considered common knowledge is that exercise is good for your mental health. Why can’t people use that as a first step on a journey to better health?
Clearly people still struggle with those messages, and we need to understand why they struggle. Furthermore, a lot of people don’t understand why and how the benefits accrue. If you’re unfit and you take the stairs, you just feel awful. It doesn’t make you feel any better. Sometimes, the benefits can come 20 years later. The medical profession often doesn’t understand how to tell people how and why exercise is healthy. It lowers your cholesterol level, yes. But almost nobody really grapples with how exercise affects your energy balance and how it turns on repair and maintenance mechanisms that are silent and invisible. And why, as we get older, physical activity is more important, not less important. So, I think understanding why things are the way they are is very empowering and useful.
How does this help people who want to be healthier to get
healthier?
The first step is for us to start to think differently about exercise – to understand why our bodies evolved to be physically active, but also how and why we evolved to be inactive. We’re told that, somehow, if we don’t take the stairs, there’s something deficient about us. But it’s completely normal, so we have to figure out ways to overcome that. Physical inactivity is a fundamental adaptation: we evolved to save energy, and that’s something we don’t discuss. We have all these myths about our ancestors being incredibly fit people. The evidence says they weren’t. They did as much as we do. They weren’t particularly strong, they weren’t particularly fast, and they weren’t particularly virtuous. They had no choice but to be huntergatherers. But they only worked a few hours a day. Typical huntergatherers did moderate activity, on average, for about two and a quarter hours a day. I mean, that’s not a lot. And they didn’t have perfect health. Is there an equivalent in the modern world?
There are almost none left. The Hadza in Tanzania are pretty much the only ones, so there are a lot of researchers going out there and, I think, changing the way the Hadza live. I only went there once and have read all the other research. I do work with subsistence farmers, studying people in Kenya, Mexico and elsewhere. They are not hunter-gatherers, but they are like them: not connected
to a market economy,
not sitting on chairs, not sleeping on mattresses, carrying stuff all day long, not using machines, not always wearing shoes. The research from them is that they’re not doing large amounts of strenuous activity.
One of your concluding points is that we need to make exercise “necessary”. How?
Childhood and young adulthood are important times in terms of setting habits for the rest of your life. We should think about schools, colleges and universities including physical activity and education about it.
What about those of us who are older?
You can never really coerce adults to do anything in a modern Western society. But what we can do is figure out ways to incentivise ourselves. The other morning, I met a friend for a run at 6.30am. It was dark, cold and raining, but I’d agreed to meet him – I’d given myself a reason to go when I wasn’t pleased to be out there. When I got back at 7.15am, it was beautiful, and I felt good. All people who exercise have found ways to get themselves to do it, right?
True, but you didn’t have to meet your friend – it’s just nice to run with someone, isn’t it?
No, it’s a social obligation. We’re coercing each other. We made it necessary, socially. I think that’s very much part of the “necessary” part. When, as humans, we are responsible to each other, we change our behaviour.
What if your friend bails, or you can’t run at the time your friend can, or you have no friends? How does one coerce oneself ?
You sign up for a race, or you just tell somebody to act as a kind of referee for your exercise plan – your partner, or anyone you know. There are all kinds of ways to do it. One argument in the book is that we should treat exercise like education. Education is a modern, strange thing. Universal literacy didn’t happen until the Industrial Revolution. The vast majority of people who ever lived never read anything in their whole lives. Now, we send our kids to school, and we do it by making it necessary, and we also try to make it fun, and we use rewards and incentives. I think we should treat physical activity and exercise in exactly the same way. Make it necessary, fun and rewarding.
“We now have to make choices that we never evolved to make”