22 Feb 2021

Professor Daniel Lieberman on why we're wired to be lazy

From Afternoons with Jesse Mulligan, 3:15 pm on 22 February 2021

When you take the escalator, instead of the stairs, don’t be too hard on yourself. We are hard wired to choose the easy way says Professor Daniel Lieberman, professor of human evolutionary biology at Harvard.

You’re not wrong or even lazy if you find going to the gym or doing workouts unpleasant. 

Lieberman wants us to take a more compassionate approach, an anthropological approach, to physical activity that keeps us healthy. 

Professor Daniel Lieberman

Professor Daniel Lieberman Photo: © 2019 The President and Fellows of Harvard College

His new book is called It’s Exercised: The Science of Physical Activity, Rest and Health and he tells Jesse Mulligan that he’s a reluctant exerciser himself.

“Anybody who claims they just get out of bed and runs a marathon for the sake of it is either very unusual or a bit deceptive.”

In the book he writes that too many people claim we were born to exercise and it’s in fact a very recent phenomenon to deliberately exert ourselves.

“They’re not making the distinction between exercise and physical activity. We certainly evolved to be physically active, there’s no question about it, but not crazy amounts and I think people often exaggerate how much our ancestors did.

“Our ancestors were physically active for two reasons and two reasons alone. One was that it was necessary and the other was that it was socially rewarding – dancing or playing. But going to a gym, getting on a treadmill and slogging for half an hour is a very strange, medicalised, commercialised way to be physically active.

“If you’re willing to do it, great because that’s healthy, but let’s not pretend it’s normal and anyone who doesn’t like to do it is somehow abnormal or lazy.”

Lieberman rejects the myth of the so-called athletic savage.

“There’s this idea that’s been floating around spread by people trying to make money off it, frankly, that people who are uncontaminated by civilisation can somehow lift amazing loads of weights and run marathons. There are even myths of pain being differently experienced by different groups which I find very disturbing.

“But our ancestors and people in non-Western societies, there’s nothing special about them. The reason they’re good at certain physical activities is because they try hard and they care about it, it’s important to them.”

He says that tribes of people who do things like endurance dancing and long-distance running do it for spiritual and prayer reasons.

“This is normal, this is how all human beings were until recently and most of us still are, though we don’t really think about it.”

Where we really differ from our ancestors is in the fact that we have to do far less physical activity in order to thrive and survive.

“In the United States, the average American walks only about 4700 steps a day – about two miles – they engage in very tiny amounts of moderate or vigorous activities. But our ancestors, hunter gatherers, they typically do around two hours of moderate to vigorous activity a day. That’s six to ten times more than your typical American.

“It’s not an enormous amount, it’s not like they’re working crazy hard all day long, but it’s still enough to generate enormous health benefits.”

Lieberman says that our ancestors, like most animals, typically spent most of their days simply sitting.

“You can’t be physically active all day but it turns out that worktime sitting versus leisure time sitting have different associations with health. There’s a much stronger association between leisure time sitting and negative health than work time sitting. That makes sense because, if you don’t exercise, you’re going to get into trouble.

“Further, it turns out there are healthier and less healthy ways to sit. What really matters is sitting duration. You and I might sit ten hours in the same day, but if I get up every 15 minutes and you get up every 40 minutes, turns out my health outcome will be a lot better.”

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Photo: Penguin Books

Exercise, he says, should be treated like education, necessary but with a bit of fun added in. He says that many people are put off by what he calls ‘exercists’ who brag about how many miles they can run and people who are unfit, overweight, or confused about where to start find it difficult to even begin.

“We need to recognise there’s nothing wrong with them, they’re actually being perfectly normal. It’s a bit like people who are trying to lose weight, it’s really hard to lose weight because you’re fighting deep fundamental adaptations that humans have to hold onto any weight that we have.”

And if people think the treadmill is a torturous, they’re not far off the mark; the treadmill was invented in Victorian England as a form of punishment for prisoners.

Lieberman says that rather than signing up for a gym on our own, which might intimidate some people, we should find ways to make exercise sociable and fun. He suggests finding a friend who will go on long walks or jogs with you. It’s also important not to be mad at yourself for not wanting to do it.

“The most common reason people don’t like to exercise is time and because they feel bad about their instinct to not exercise. First of all, knowing that it’s a fundamental instinct helps us overcome that.

“The time one is even more important because it’s important to recognise that no matter how sedentary you are, any exercise is better than none. Just ten minutes a day, 60 minutes a week, can lower your rate of mortality by 30 percent, it’s extraordinary. And 150 minutes a week – 21 minutes a day – can lower your mortality rate by 50 percent.”

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