Why Do We Exercise?

en in humanity • 10 min read

In the last post about food, I said that food is only one part of a healthy lifestyle. To stay healthy, you need to do more than that, avoid smoking and drinking, and mostly do exercises. But why? Exercising is kind of recent invention introduced by the modern world. Indigenous people do not exercise; actually, they don’t even understand why anyone would exercise.


Everything around us is covered under stories we believe in. It doesn’t matter if it’s religion or ideology or your common sense. We changed a lot how we live since the start of the human era about 12 thousands years ago, but our body is still the same. To see the difference between living with nature and living with our stories, we need to understand how humans evolved and our history.

Unfortunately, we don’t have any records to help us understand how we evolved thousands and millions of years ago. We have only a few skeletons, sometimes with tools used by those people. Even though we found a lot, we are still missing significant links between evolution steps.

We can only use our imagination and guess. One way how to improve the guess is by studying our closest relatives. That is chimpanzees and bonobos, or also gorillas. What we learned by observing our relatives? That we are super active, compared to chimpanzees and gorillas. They live on low energy diet and thus have a very inactive lifestyle.

To find a reason for the difference, we should explore how we use calories. There are five ways to use calories (not used for basic functionality, such as brain, breathing, or circulating blood): either for reproduction or growth, which is the most important from the natural selection perspective. Another spending goes for activity, such as obtaining food, or maintenance, such as repairing the body after activity. And lastly, calories could be stored in fat, and in this case, also retrieved back to be used for something else later.

Humans need more calories to raise a child and more calories to grow than other great apes. Therefore we eat more diverse food to get more energy, and therefore we cook our food which gives us even more energy. Thanks to more available energy, we can also run faster and for longer distances. But we are more prone to a scarcity of calories, and we are more averse to needless activities—for example, exercise. (Of course, we cannot say what the cause or consequence is; as always, it went more hand-in-hand. The critical fact is that we differ from other great apes by having more energy.)


Before the beginning of the human era, when significant changes started happening, all humans were hunter-gatherers. As in the case of previous evolution steps, also here we lack much valuable information. That’s why Hadza people, indigenous people in Tanzania living closest to the traditional way of life to hunter-gatherers, are famous by scientists. You can find paper covering anything you can think of about the life of the Hadza people.

Average Hadza sleeps about six hours in summer or up to seven hours in winter. Most of the day, about 12 hours, average Hadza sits. But the important detail is that the sit is not continuous and completely inactive as for modern humans in front of screens. Usually, Hadza doesn’t sit in one position longer than about 20 minutes. Also, Hadza uses different sitting positions (real sitting is only about nine hours of the day, the rest is filled with roughly two hours of squatting and one hour of kneeling). Besides resting, Hadza does four hours of light activity (such as walking, including 20 thousand steps), two hours of moderate activity, and 20 minutes of vigorous activity a day.

What can we take from it? A lot of things. The first and most important thing is that inactivity is a fundamental part of human life. We need to be inactive; that is the only time when our body has time to repair from any damaging activity. That is essentially anything; even just breathing right now is damaging you bit by bit on a microscopical level. Don’t worry, though. That’s perfectly normal: we call it aging.

But there is a twist, of course. Because if there is no twist, we could rest all day long, and we would live long, healthy lives. Many people live that way, and as a result, we have the obesity pandemic. Idleness doesn’t lead to the use of extra energy (not used for growth, or reproduction, or activity) for maintenance but storage (fat). Obesity is not an issue by itself, though; the problem is that too much fat and sugar in the bloodstream is causing all kinds of inflammations and other illnesses.

Hadza’s life span is about 70 years. The modern world increased an average life span by about ten years, but the healthy span is now much shorter. In the case of Hadza people, they live fully nearly until the end, whereas in modern society, the health of inactive people goes down already after 50. Medicines can slow down aging but not significantly to avoid the changes. So instead of living 70 healthy years and enjoying extra ten years, we have a shorter healthy life with 30 years of slow death.


There are many hypotheses why this is happening. I like the one described in the book Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding by Daniel E. Lieberman: we were not evolved to be extremely inactive as we are today. Evolution is just about natural selection, and natural selection cares only about reproduction and growth. It makes sense that our body doesn’t care about anything else but that. But activity such as walking, running or carrying stuff is essential for survival (at least it used to be). Therefore our body learned to trigger repair mode only after activity.

With this hypothesis, we can also explain why these days, so many people die (about a quarter of all deaths) due to cancer. As said already above, inactivity means more energy for storage, and too much fat is causing inflammation which can mutate cells. As also stated above, natural selection is about reproduction, therefore the body uses extra energy for it by producing, for example, estrogen, which increases the chance of mutated cells and causing breast cancer. That mutation gets energy again from extra energy not used by the activity. And because there was no activity, the body does not even trigger maintenance mode, which can fix damaged cells.

Homo genus evolved to need more energy than its ancestors. Thus humans learned to skip any unnecessary activity to survive even when it’s hard to find food. We learned it so well that we didn’t even notice how our inventions, such as moving walkways, escalators, elevators, cars, carts, suitcases on wheels, tap water, remote controller, and so on, are making us too inactive and causing issues. We always had to relax (that’s why Jews have Shabbat to relax on Sundays), but now we need to compensate for our inactivity.

Two hundred years ago, everyone would laugh at you to be active for no purpose; even more, no one would understand why to pay so much for exercise. Indigenous people living today still don’t get how we could make a new market by forcing people to exercise. There are many opinions about what is healthy and what is not. How many minutes a day you should exercise and so on. But the truth is, like with the food, there is no unique healthy way.

Everyone is different, so everyone needs something else. But there are two crucial facts: both too little and too much activity is harmful to your health. Why too little is hopefully clear, but be careful not to overdo it (even though I doubt most people would have this issue). As I said, we evolved to relax. We need to give our bodies some time to do maintenance. Doing a lot of exercises means not much time and energy for maintenance, thus decreased immunity. It’s counterproductive. That’s why the elite sport is not that good for you. Craziness to be the fastest or strongest person is new to our age, too. Hunter-gatherers don’t have to be the best in one category. For them, the trade-off of all abilities is essential. For example, sometimes it’s beneficial to be strong, but sometimes you need to be swift; being good only in one category as a hunter-gatherer means a disadvantage.

Modern Age

Sitting is not an issue, as many people say. Inactive prolonged sitting is the issue. That’s why standing desks are popular. Because standing is consuming more energy than sitting. But you shouldn’t stand for too long in a row. It’s more about changing posture every few minutes—forget about healthy posture with a straight back; the best posture is always the next one. Take also a break for a short walk from time to time. For example, have only one glass of water on your desk to be forced to go for a refill. All that helps to reduce chronic inflammation.

As you can see, if you have a job where you sit a lot, you are fine. You can make it work without significant effort. But what is more crucial is what you do outside working hours. If you go home to occupy your couch and watch inactively TV, that’s a much more severe problem. You have to compensate for what you are missing.

Hunter-gatherers walk a lot to collect food and water, up to 20 thousand steps a day. They carry food and water around. Some of them run to hunt animals, but all of them dance. We don’t know about any non-industrial culture which wouldn’t dance. For example, Hadza people can start dancing after dinner and stop only to go to sleep.

Experts try to draw many conclusions on healthy exercise. In the case of diet, experts can agree only on one thing: eat more veggies! It’s similar in case of movement: better some activity than none. If you need some specific guideline, there is consensus between experts (changed several times but only slightly) since 1995: kids should exercise about an hour a day, adults 30 minutes of cardio five times a week (to compensate for walking and running), and weights exercises twice a week (to compensate carrying stuff).

Note it’s important to focus on a time limit and not other goals. Giving yourself a plan to run several kilometers can make you sad if you don’t make it. Or you can skip it because you know you will not make it in time that day. It’s not about numbers and competing with friends. It’s about going out and move a bit. I use a calendar from Kurzgesagt to simply mark days which I exercised. Just a simple mark without any condition.

It’s also good to have a frequent schedule than catch-up at the end of the week. Our body triggers maintenance mode after activity, and it seems it can go for two hours or even two days (it depends on the level and duration of activity). This is also the moment when your body repairs cells after aging. But this is just a side effect. Your body triggers repair mode based on your activity; it will not fix the whole week of inactivity after one day of exercise.

By the way, you should not lessen your activity over time. Hazda people are active till the end. On the contrary, they are even more active as grandparents. Parents cannot take care of and feed their kids alone; therefore, grandparents provide food for grandchildren too. That’s how they stay fit. I like what the author of the book Exercised wrote: We evolved to be physically active as we age, and in turn being active helps us age well.

One more note on modern pills: we have drugs that might help. We might even have tricks to trigger maintenance to some extent. But our body is much more complicated. The activity also produces hormones, for example, dopamine that makes you happy, or serotonin which improves your memory and sleep and reduces anxiety. Taking pills means you will need more medicines, and who knows all kinds of consequences. Not worth it.

So, which activity is missing in your active life?

For me, it’s dancing right now. Exercise is not fun. No one wants to do it unless they do it because of opioids called endorphins. You have to make it mandatory or fun. I like to dance salsa which is my fun and was my regular activity to stay fit. I understand that closing fitness, or dance and other events help reduce the spread of covid, but I believe this is very shortsighted (check out my post about covid and lockdowns). It might work now, but in the long run, it will cause collateral damage: an even worse obesity pandemic.

It’s crucial to find a pleasant way to exercise even in such hard times.

I will finish with the conclusion from already twice mentioned book Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding by Daniel E. Lieberman (you should absolutely read it, it’s a fantastic book and it will explain what I tried to describe in this post in much more profound level): Make exercise necessary and fun. Do mostly cardio, but also some weights. Some is better than none. Keep it up as you age.

You may also like

en Human History: We Are Animals, June 29, 2020
en Alternative to Lockdown?, February 12, 2021
en We Need Fake Stories, January 4, 2021
en Our Fake Stories are Flawed, January 6, 2021
en New Religion: Climate Change, February 1, 2021

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