My eldest son, now 18, has a very disabling genetic disorder; since childhood he has been cared for by a team of doctors at Columbia Medical Center in Manhattan. His geneticist, one of the most formidable intelligents I have ever met, had worked on the Human Genome Project in the 1990s, sequencing the LEP gene, which encodes leptin, a hormone that helps inhibit hunger pangs. He longed to distill his research on a eureka pill for those of us susceptible to midnight attacks in the fridge, that extra slice of chocolate cake, a Holy Grail of treatments. In the end, however, she and her colleagues fell short. “It’s all about dieting and exercising,” she once told me, “just like her mother asked when she was little.”
“Exercise,” a new and vigorous work by Daniel Lieberman, Edwin M. Lerner II Professor of Biological Sciences at Harvard, examines how and why exercise is so good for us when as a species we have evolved as moccasins to conserve calories for lean seasons. Lieberman opens the book with a play on words: the title refers not only to physical exertion in search of good health, but also to the adjective exercised, “to be upset, anxious, worried, harassed.” As he knows, most of us feel in conflict with exercise; the idea of 30 minutes on an NordicTrack elliptical or deadlift in the gym can raise our blood pressure.
But is there any evolutionary basis in our collective fear? Lieberman argues that even our ancestors down the railroad track were loose. When we analyze various cultures around the world, or even our close relatives of primates, such as chimpanzees, we detect a clear pattern: our species is adept at devoting much of our time to spending time in order to conserve. calories. Throughout the book, Lieberman refers to the Hadza, a people seeking food grouped in Tanzania; despite the profound differences between their routines and ours, between their diets and ours, common biology is not so different. They sit around the camps at about the same pace as those we are trapped in table work.
Consider sitting and if it’s as bad for us as smoking cigarettes (it’s not)[HC1] [k2]. And he reflects on the marketing of fitness. “For me, the apotheosis of what is good and bad about contemporary exercise is the treadmill. Treadmills are incredibly useful, but they are also noisy, expensive, and occasionally treacherous. . . The only way to endure the boredom and discomfort of a treadmill workout is by listening to music or a podcast. What would my distant hunting ancestors have thought of paying a lot of money to suffer due to unnecessary physical activity on an annoying machine that gets us nowhere and gets nothing? “
There is a dry and didactic quality to the exercise; Lieberman is a first-rate scientist and a compelling writer, but the book lacks the stylistic spark of a Robert Sapolsky or David Eagleman. And yet Lieberman’s clarity never flows. When the book goes into prescriptive sections, should I focus on cardio instead of weights? Are gym workouts still beneficial as we age? – Easily recognizes that the data is more suggestive than true. (A runner, leans toward cardio as a favorite exercise.) He is particularly good at breaking myths, organizing chapters around discrediting assumptions about what constitutes fitness and health. Eight hours of sleep may not be the most effective way to rest. Charles Atlas, on the other hand, evolved, as a chapter title describes it, “from thick to scrupulous,” taking advantage of our more graceful forms about, say, most Neanderthals. His answers to physiological questions: “Running badly for the knees?” “Should my 90-year-old grandmother put pressure on me every week?” – dispel lazy platitudes.
They also inspire. He presents his case on preventive care, often wasted by Americans as a violation of their freedom to be sofas. “I am aware that people like me usually sound like records. . . . However, don’t react this way because the cancer-fighting potential of exercise is underestimated and inefficiently explored. . . . Just as natural selection favors humans who acquire and then expend as many calories as possible in reproduction, selection that drives cancer favors malignant cells that acquire as many calories as possible and then use them to create more copies of themselves. ”It highlights the main culprits: reproductive hormones, sugar, inflammation, and antioxidants, and illustrates why exercise may be our most powerful weapon in preventing the emperor from all disease.
To get back to the Columbia geneticist’s point: if “Exercise” is occasionally read in her mother’s tone in a stern voice, moving her finger and begging her to eat her vegetables and be able to jog around the neighborhood, all this is good. Lieberman has accomplished his mission. But the science behind its arguments is revealing, with exciting implications for evolutionary biology. Written in fast-paced prose, with ample graphics, “Exercise” is an excellent compendium of the broad medical benefits of exercise and a roadmap to getting out of our pandemic to improve health.
Hamilton Cain is the author of “This Boy’s Faith: Notes from a Southern Baptist Upbringing” and a member of the National Book Critics Circle. He lives with his family in Brooklyn, New York
Exercise: Why something we have never evolved to do is healthy and rewarding
Daniel Lieberman
Pantheon, 464 pages, $ 29.95