A Standing Ovation to Human Evolution

In the last few years, we’ve been inundated warnings that sitting is killing us, or that the best way to reduce stress is yoga. But what if we don’t like yoga? And do we really need to feel bad about all the work we’re doing, which largely takes place while seated?

Yet what takes this conversation to a completely different level is Scientific American’s recent article, “Evolved to Exercise,” written by evolutionary anthropologist Herman Pontzer. Pontzer shows why moving is essential to our biology, our physiology, and even our mental health.

Diagram of human evolution, from Smithsonian.

While it’s a common misconception that we evolved from great apes, we do share a common ancestor. Between 6 and 8 million years ago, chimpanzees and bonobos went one way and the predecessors for humans went another. Then, 1.8 million years ago, our ancestors developed a body that was proportioned much like we are today — a vertical torso, a strong pelvis, an S-shaped spine. This body was built to travel long distances at little cost; it takes us fewer calories to travel long distances on two legs than it does on four. I find it pretty extraordinary that our slow-twitch muscles, which are good for endurance, may have allowed us to exhaust our prey by outrunning it.

A comparison of muscle and bone structure in humans vs gorillas from Britannica.

Not only has Pontzer studied the geological and biological records, but he has also spent time with the Hazda of Tanzania because they live as our ancestors did — as hunters and gatherers. (Note: We’ve only been subsisting on agriculture for the past 12,000 years.)

What Pontzer found was that The Hazda typically walk 12,000 to 18,000 steps a day, far more than the average American and definitely more than me (I usually aim for the suggested 10,000 steps). At this point, it’s easy to think about how inactive we are by comparison, and link that to increasing incidence of obesity and diabetes, but Pontzer’s work has shown that the number of calories burned by the Hazda is not much different than a typical American. In other words, according to Pontzer, there’s no link between a sedentary lifestyle and obesity, diabetes or heart disease, which have much more to do with diet.

Instead, the links between activity and health lie elsewhere. We keep hearing how movement can slow the “normal” deterioration that comes with age — if you keep moving, your muscles stay biologically “young” , and endurance sports are most likely to keep our telomeres long. (Telomeres are bits of repetitive DNA at the end of our chromosomes, and they shorten as we age, affecting our health and life span.)

“…exercise is not optional, it’s essential,” Pontzer writes, “Our bodies are evolved to require daily physical activity, and consequently exercise does not make our bodies work more such as it makes them work better.”

It’s good for our immune system. It can delay cognitive decline. It makes cancer in reproductive organs less likely. So, the reason it’s better to stand than to sit, or at least to take breaks from sitting, is not because a million listicles have commanded you to do so, but because of its many positive effects on the body, not all of which we fully understand.

And the good news for aging bodies, or for those of us who want to take it easy, is that the way we move doesn’t have to be high-intensity. What matters is that we do it at all.

For instance, whenever my 95-year-old mother comes to visit, she becomes more active by the day. Where she lives, no one really encourages her to move, unfortunately, so she’s out of practice. But when she’s with me, she’s going up and down the stairs (with me behind, spotting her just in case), and she feels motivated by how much she improves during our time together.

At the end of the day, what is most encouraging about Ponzter’s research is that when we commit to moving, we’re actually committing to a better understanding of ourselves and our ancestry. Our ears no longer perk up when we hear something is good for us, but when we learn that this is what we were built for, then I think there’s a strong chance we’ll listen.