Johnny Kelley did everything the expert’s say we should if we want to age well: He started exercising young and never stopped.
Too small to play football for his local team in West Medford, Kelley turned to running at 18, and launched the most storied marathoning career in Boston history. Over the years, he ran in 61 Boston Marathons, winning twice and placing second seven times. He also ran the New York Marathon 15 times (he won it twice), and made three US Olympic teams. Today, at 93, he lives in East Dennis and still jogs, swims and goes to the gym several times a week to work out with his trainer.
Exercise, said Jay Olshansky, a senior scientist at the Center on Aging at the University of Chicago, is the closest thing we’ve got to a fountain of youth.
Granted, even the most conscientious of athletes cannot finally escape the ravages of time. Kelley finally gave up his beloved Boston Marathon at age 84, and, these days, he’s more of a walker than a runner. But his very prowess, even now, suggests that human beings can remain strong and fit for many more years than most people think.
Vigorous exercise such as running and brisk walking can add years to your life – about 2 1/2 years if you start before age 35; six months if you start at 75 – largely by lowering your risk of heart disease, cancer and other chronic diseases. Strength training (weight lifting) has not yet been shown to add years to life, but it clearly boosts the quality of life by giving you the muscle power to move around, take care of yourself and remain independent.
But how far can you push the limits? How good can an aging athlete really be? The short answer, sadly, is probably not quite as fit, fast and strong as you were in your youthful heyday, assuming you had one. But you can be a lot fitter, faster, and stronger than you might think; even if you take up exercise after years of sloth.
No matter what you do, for instance, “VO2-max,” or aerobic capacity – the maximum rate at which the heart, lungs and muscles can burn oxygen to make energy – declines with age. If you don’t do regular, aerobic exercise, it falls 10 percent per decade after age 25, several studies have shown. If you do, it declines at half that rate.
But that’s not as discouraging as it may sound. In fact, some aging jocks nowadays can do what was once thought impossible. A century ago, even world-record holders couldn’t run a mile as fast as some 40-year-old masters athletes do today, according to a recent editorial in the Journal of Gerontology. The increasingly impressive performance of older jocks may be due in part to the fact that, as baby boomers age, there’s a bigger pool of older athletes out there, which allows some to become superstars.
In a sense, the most powerful message emerging from recent research into fitness and aging is a simple one: You have to keep exercising if you want to maintain strength and prolong life, even if you were a star jock early in life.
One study, published in 1996, showed that even men who were elite athletes in their youth were no better off than sedentary folks if they stopped working out. The men were rowers who won a silver medal for the United States at the 1972 Olympics, and researchers subjected them to numerous physiological tests that year, then again in 1982 and 1992. After the Olympics, most of the men put their energies into careers, not rowing, said William Evans, the senior author of the study and an exercise physiologist at the University of Arkansas for Medical Sciences. And their fitness levels declined steadily.
But one man kept training all those years. He was still at 90 percent of his aerobic capacity 20 years after the Olympics, though the tests did show he had lost some muscle power (a measure of combined strength and speed) and that his muscles were more susceptible to fatigue than they had been.
Years ago, when exercise physiologists first began studying fitness and aging, what they most wanted to find out was whether regular exercise reduced the overall risk of death. It clearly does, as two pivotal studies, since confirmed again and again by other research, showed.
One 25-year study of 17,000 Harvard graduates by Dr. Ralph Paffenbarger showed that expending at least 2,000 calories a week in exercise (roughly equivalent to jogging two hours a week) adds a year or more to life.
Another study, by Steven Blair at the Institute for Aerobics, part of the Cooper Aerobics Center in Dallas, was equally dramatic. Blair and his colleagues followed more than 10,000 men and 3,000 women and showed that the least fit men died from all causes at the rate of 64 per 10,000 compared to 19 per 10,000 among the most fit. Among women, the least fit died at more than four times the rate of the most fit. Perhaps even more important, said Dr. Ken Cooper, the head of the center, you don’t have to be among the most fit to get the benefits; even moderate fitness has a profound, positive effect on longevity.
But in recent years, exercise physiologists have turned their attention increasingly to muscle strength and power as opposed to overall, aerobic fitness. And they’ve found both good news and bad.
It’s clear that people who don’t keep their muscles strong by lifting weights lose about one third of a pound of muscle per year, said Miriam Nelson, an exercise physiologist at Tufts University. Researchers are still trying to figure out how much of this loss can be offset by regular weight lifting, but a Scandinavian study a decade ago showed that older men who did regular strength training had as much muscle mass as younger men. (Interestingly, older runners and swimmers, who were aerobically fit, did not preserve their muscle mass as well.)
Still, there does appear to be a biological wall: We are born with all the muscle fibers were ever going to have. Muscles can and do get bigger and stronger with use, even among people 100 and older, as a number of studies since 1990 have shown. But the number of fibers doesn’t increase.
“There is immutable decline” in muscle mass in part because of a decrease in the number of motor nerves that activate muscles, said John Faulkner, a muscle physiologist at the University of Michigan who, at age76, still runs 4 to 6 miles a day.
In fact, he said, its atrophy of muscles that is the biggest factor in the decline of athletic performance with age. Even so, he said, it pays to stay active and do everything you can to keep muscles strong as you age.
“The person who is active will reach some threshold at 95 or 100. But the inactive person may reach it at 60.”
In fact, research suggests that exercise can make old muscles look a lot like young ones, both under the microscope and in the gym.
Aerobic exercise makes muscles richer in myoglobin (a substance, like hemoglobin, that carries oxygen), capillaries (small blood vessels) and mitochondria, the structures in cells that produce energy, said Evans of Arkansas. Strength training confers those advantages plus another one: The muscles of people who lift weights regularly are bigger and contract with greater force than those of people who don’t.
Scientists who study aging and fitness are also finding that some types of muscles age faster than others. Fast-twitch muscles, which are light colored (like the white meat in turkey breasts), are the type used for speed. This kind of muscle seems to fatigue more quickly and decline more rapidly with age.
Slow-twitch fibers, on the other hand, which look red because they are rich in myoglobin, are for endurance, and they seem to decline more slowly with aging. This may explain why older athletes can’t run or swim as fast as young ones, but can do quite respectably in endurance events like ultramarathons.
Power, which includes speed as well as strength, is also a growing focus of scientists who study aging athletes. In fact, new research suggests that power may be even more important for maintaining daily activities than strength, said Roger Fielding, an Boston University exercise physiologist.
Power seems to decline faster with age than strength – 20 percent per decade versus 10 percent, in people who don’t do special training. But Fielding and his team have just completed a randomized study showing that in older women (average age, 72) muscles can be trained for increased power. The weight-lifting exercises are much like those used in strength training, but in strength training, the emphasis is on lifting weights slowly, while in power training, the key is lifting weights very fast, Fielding said.
The bottom line, exercise physiologists say, is that inactivity, more than age per se, is the great enemy of fitness and health.
One Dallas study, in fact, showed that male college students forced to stay in bed for three weeks wound up with changes in fitness and muscle mass comparable to 20 years of aging.
Most of us probably don’t have whatever combination of good genes, good habits and good luck that makes Johnny Kelley such a dazzling older athlete.
But you don’t have to run for decades like Kelley to be extremely fit as you age. You can just follow his advice, which is, if you don’t like to run, walk: “Walking is the best exercise in the world.”