Eat less, move more, laugh whenever possible—and have long telomeres. That’s a distillation of Gary Merrill’s prescription for longevity, gleaned from his four decades as a physiologist as well as from the extensive research he completed for his latest book, Our Aging Bodies (Rutgers University Press, 2015).  In it, the professor of cell biology and neuroscience at the School of Arts and Sciences catalogs the ways in which the human body changes over the course of a lifetime. He also maintains a personal catalog of his own body’s responses to getting older, and he is remarkably sanguine about the process. Whether that comes from a lifetime of healthy living, a philosophical bent, or religious reflection (Merrill is a practicing Mormon), he appears to be at peace with the idea of aging. Asked why we age, he reflects for a second, then responds, “I’m no expert, but I think it might be in preparation for another state of existence.”

If that’s so, Merrill may have to wait some time for his own metamorphosis. Trim and energetic, the 67-year-old seems the picture of robust good health. His religious affiliation may have something to do with that. In Our Aging Bodies, he cites the research of James Enstrom, an epidemiologist at the University of California, Los Angeles, who has been studying Mormons in Southern California for several decades and found that they’re not just healthier than the rest of us, but also tend to live eight to 10 years longer. Merrill attributes that, in large part, to the Mormon diet and health code known as the Word of Wisdom, which encourages the  consumption of fruits and vegetables in season, as well as wheat and wheat products, and minimal meat. (It also forbids coffee, tea, tobacco, and alcohol.) 

While Merrill’s book focuses on the processes involved in aging, it also offers tantalizing glimpses into the elements that may contribute to longevity. Sybarites, be warned: chief among them may be self-control. The research he uncovered on centenarians and supercentenarians (those who live to the age of 110 or beyond) has convinced him that discipline, or at least lifelong moderation, is essential to living a very long life. “Look at any picture of centenarians anywhere,” he says, “and you won’t find a single one who’s obese.” He admits that genetics probably play a role in their longevity as well, but he adds, “I think they’re also more disciplined than the rest of us.” If so, it’s paying off in more than just the number of their days. Research reveals that those who live to 100 or older are uncommonly healthy until the very end of their lives.

Even more disciplined than Mormons and centenarians, perhaps, are members of the Calorie Restriction Society and similar groups, who believe that severely restricting caloric intake (by anywhere from 20 to 60 percent) may be the secret to longevity. Many animal studies, though not all, appear to back them up, and, notes Merrill, early research on humans is “most promising.”

Of course, a healthful or ascetic diet alone isn’t likely to guarantee health and longevity. Turning the lens on his own life, Merrill—who notes that “I’ve never been a sitting-around type of guy”—acknowledges that physical activity is essential as well. He believes that the human circulatory system is designed to last 120 years or so—with proper upkeep, of course. Consider, for example, that healthy collateral circulation—blood flow through the smaller blood vessels that branch off larger, mainstream arteries—can protect us from the potential damage caused by blocked arteries, and that the best way to increase collateral blood flow is to be active. Activity, Merrill notes, improves more than blood flow. A recent study found that Senior Olympians (who must be 50 or older to participate in the National Senior Games) had significantly higher bone density than their more sedentary peers—and bone density can protect against hip fractures, which are a major cause of disability and increase the risk of death among the elderly.

Discipline in diet and exercise only goes so far, however, as is evident in the apparent correlation between humor and longevity. While researchers aren’t entirely certain of the physiological mechanisms behind the connection, Merrill notes that “people who laugh at things are generally more laid back and better able to handle stress.”

In fact, handling stress may be another key to longevity. A number of studies have linked anxiety to a shortening of telomeres, stretches of DNA at the end of chromosomes. That’s significant, explains Merrill, because the shorter your telomeres, the less likely you are to be long lived. Adults who were bullied as children, for example, tend to have shorter telomeres as adults, as do women who suffer from phobias. Luckily, many factors appear to affect the length of telomeres, including diet, exercise, and even, according to a recent study, paternal age at conception. Apparently, having an older father confers longevity, not just on you but on your offspring as well.

Although we can’t change the past—or alter our genes, which clearly play a role in aging—Merrill offers some simple advice that most of us can put into practice: “Be your own physician,” he says. “Eat wisely and don’t stop being physically active—that combination should go a long way toward sustaining you.” He offers a parting caveat: “Age gracefully because, in the end, you’re going to age no matter what you do.” •