Review ‘exercised’: Born to run?

Doctors, fitness gurus, and the media incessantly remind us that exercise leads to a healthier, longer life and thinner, more attractive bodies. We celebrate feats of sporting dexterity and lavish attention to superhero actors with almost pathological torsos. So why, if all of this is so good for us, do most of us have exercise relationships ranging from love to hate to hate? Why do we rely on hectoring surveillance technologies like smart watches to get us through the “mandatory” daily steps?

The title of “Exercise” is a clue: there’s something neurotic, annoying, and anxious about our obsession with physical activity. In the book, Mr. Lieberman confronts a dozen myths about fitness and health, dedicating a chapter to them. His goal is evolution — he is a Harvard paleoanthropologist with a specialty in human locomotion — and he studies the effects of energy movement that consumes energy in the laboratory and in various groups of people around the world.

In one chapter, for example, Mr. Lieberman addresses the myth that making sure is bad for you. Disappointingly, he finds the myth to be true, but not in the way most people assume. Contrary to conventional wisdom, leaning postures do not cause back pain, as evidenced by both research on office workers and the comparison of sitting styles around the world. The real problem is that people don’t get up and move enough. As scientists begin to understand this, long-term inactivity and increased fat around our organs increase the risk of chronic inflammatory diseases, such as arthritis and type 2 diabetes. Mr. Lieberman’s recipe ? Don’t be inert for too long. Take a break. Get up. Or at least “scratch without shame.”

Until about two million years ago, all of our ancestors lived in search of wild food. Human physiology and anatomy were adapted to these ancient lifestyles in ways that may not be optimal today. It’s not that we’re worse off for this story; in fact, 21st century Americans live longer and healthier than those of any earlier era. But sometimes the tricks we evolved to solve old problems upset us today.

To understand the challenges of modern life, anthropologists rely on the observations of the few human groups that live in search of wild, uncultivated food. Some of the best parts of “Exercises” are the stories of Mr. Lieberman on his and other work with these modern food groups, such as the Hadza, who inhabit an arid and relatively inaccessible corner of Tanzania. His days include a few hours of physical activity to find food, dig tubers, hunt and collect honey. The Hadza spend much of their time sitting and socializing. Like other peoples who seek food on subsistence diets, they find Westerners ’obsession with exercise strange.

Anthropologists are wary of widespread data from the Hadza and other populations because all current foragers integrate into the world economy in complicated ways. Mr. Lieberman is candid in the face of this challenge and explains how scientific research itself has become a cottage industry that sustains the Hadza community. The worst risk is that individual observations of the research will turn into scientific tales, what Mr. Lieberman calls the “myth of the athletic savage.”

In this regard, “Army” makes important advances in the subject of research by which Mr. Lieberman himself has become best known: the physiology of human functioning. In the early 2000s, Mr. Lieberman collected some skeletal traces of ancient Right man and physiological data from human runners to suggest that the endurance race was part of what made us human. The idea was that ancient hunters used a slow but steady race pattern to track animals and chase them to exhaustion.

In “Army,” Mr. Lieberman visits a group of people who inspired his ongoing research, the Tarahumara people of northern Mexico. The group became famous in Christopher McDougall’s 2009 book “Born to Run,” which brought the history of their ultramarathon races to a wide reading audience. In “Army,” Mr. Lieberman describes his visit to observe a traditional Tarahumara race. He marvels at a counterintuitive observation: Tarahumara who race do not train for them. Long races are rare social events that bring the community together, but relatively few people participate directly. The experiences of runners are similar to those of ultramarathons in the United States, with suffering and exhaustion. But the cultural meaning of the activity is different: it is less a competition than “a powerful form of prayer” that, for runners, “induces a spiritual state of transition”, making it difficult to generalize in any notion of human origins.

Some “Exercise” passages suffer from an excessive focus on the caloric bottom line. For animals that live and breathe, the balance between energy intake and expenditure matters as much as the financial balance of a business. Still, reducing the rich life event to metabolic inputs and outputs tends to make human existence sound as dry as an accountant’s ledger. In that sense, my favorite excerpt from the book is about dance. Dance in many societies is a physical activity related to ritual, a very social activity with a deep symbolic meaning for its participants. It reminds us that beauty, joy, and rites of passage are fundamental to human life and that physical activity can be exuberant and ecstatic.

For those waiting for a reason to hide in the closet during gym class, this is not your book. Science confirms many ways in which physical activity is valuable for a healthy life. Still, I find Mr. Lieberman’s voice of moderation welcome in a world where barefoot running and paleo diets have become a fad. (“Make exercise necessary and fun,” he says. “Some are better than none. Keep it that way as you get older.”) Instead of looking at a mythological view of our evolutionary past, we should look at our around with a wider range. of real humans, all of them moving — happily — through their lives. Exercising is a start.

Hawks is a professor of anthropology at the University of Wisconsin-Madison.