FORESTALLING THE AGING PROCESS

As we get older, our bodies change. It seems to take us longer to recover from anything: an injury, a cold, or a workout. We have aches and pains where we never had them before, and we often find that once easy physical tasks are now difficult or impossible. For most Americans, aging is synonymous with inexorable physical decline. But how much do we decline with age? Can exercise forestall the ravages of the aging process?

The One-Percent Rule

For years, gerontologists had an ironclad rule of thumb: after age twenty-five, there was about a 1 percent decline per year in a host of physical attributes, from maximum oxygen uptake (VO_{2 max}) to strength and speed. Thus, a person could expect to decline about 25 percent between ages twenty-five and fifty. Numerous studies of the general population bore out this conclusion.

With the advent of Masters sports in the early 1970s, however, people began seriously questioning the one-percent rule. How much of the decline, they asked, was caused by aging itself, and how much by a sedentary life-style?

A long-term study I am conducting and a smaller study by Jane A. Moore, M.D., provide good news: almost all the decline may be the result of a sedentary, unhealthy life-style. The guiding principle is “use it or lose it,” and most Americans simply do not exercise enough. If you live like a couch potato, you will come to resemble one. But if you exercise regularly, you can retain most of the strength and vitality of youth. This view is supported by anthropological studies of more physically vigorous peoples, such as the Abkhazians, among whom men and women remain robust and energetic well into old age.

Earlier studies on the effects of exercise were less encouraging. They seemed to suggest that training had only a slight impact on the one percent-decline-per-year rule. But these studies either followed moderate exercisers over relatively short periods of time or looked at different people at one point in time. Meanwhile, anecdotal evidence suggesting that there were “exceptions” to the rule began to accumulate.

By the 1990s middle-aged superstars became almost a cliché in a number of sports. At age forty-three, Nolan Ryan was crowned the major league strike-out king; tennis ace Jimmy Connors at age thirty-nine battled his way into the semifinals of the U.S. Open; forty-something George Foreman and Larry Holmes found themselves once again among the world’s top-rated heavyweight boxers; and near-forty-year-old Robert Parish, the seven-foot center of the Boston Celtics, enjoyed one of his finest seasons in the NBA. What does it all mean?

Masters Swimming: A Living Laboratory

For scientists studying the aging process, Masters swimming provides a natural laboratory with tens of thousands of subjects. For the first time ever, we can follow the changes that occur in conditioned athletes over time. Moreover, swimming is an ideal sport to study because in it performance can be measured precisely, to the hundredth of a second.

That is exactly what I have done. Instead of comparing the performances of different people at one point in time, I have studied the same individuals over a long period. This is known as a longitudinal study. Such studies are now possible because Masters swimming is over twenty years old, and we have data going back to 1971. Ultimately, I plan to follow the same people over a lifetime—perhaps fifty years or more.

How the Study Was Done

Because there were relatively few Masters swimmers in the early 1970s, I began this study using performances from 1975. Looking at six representative events—the 100- and 500-yard freestyle, 100-yard backstroke, 100-yard breaststroke, 100-yard butterfly, and 200-yard individual medley—I picked out the third-best time in the nation.

Swimmers were assigned to appropriate “age cohorts.” Cohort A, for example, consisted of people who were in the twenty-five to twenty-nine age-group in 1975. They were born between 1946 and 1950. Cohort B was composed of those in the thirty to thirty-four age-group in 1975, and so on, all the way to Cohort H, men and women who were aged seventy to seventy-four in 1975.

The study then compared the third-best times of each cohort in each of the six events every five years. For example, Cohort A was twenty-five to twenty-nine in 1975, thirty to thirty-four in 1980, thirty-five to thirty-nine in 1985, and forty to forty-four in 1990. In the 100 free, this cohort produced the following times: 49.04 in 1975, 49.14 in 1980, 50.34 in 1985, and 49.82 in 1990. Thus I was able to measure how performances changed over fifteen years and four age ranges.

What Was Learned

The results obtained were in startling contrast to studies conducted with sedentary people. I believe the evidence is overwhelming that most of the decline associated with aging is caused by inactivity rather than the aging process itself. Folks who swim regularly can perform physically at levels typical of much younger individuals in the general population.

Here are the highlights:

• The one-percent-per-year-after-age-twenty-five rule applies only to a sedentary population. The decline among Masters swimmers is a small fraction of one percent. Figure 5.1 illustrates how the physical abilities of Masters swimmers change with age.

 Figure 5.1. Percent Change per Year in Physical Ability of Masters Swimmers

• For people who swim regularly, physical decline begins not at age twenty-five, but in the mid-thirties. Men are actually faster in their early thirties than in their late twenties.

• The change that occurs with age is not linear. The rate of decline increases gradually as we grow older. Decline for regular swimmers begins, almost imperceptibly, in the mid-thirties. At that time it is 0.04 percent per year—one twenty-fifth the rate among the sedentary. In the early forties, the rate of decline is 0.13 percent per year—about one eighth the rate among nonswimmers. As Figure 5.2 illustrates, these differences are cumulative.

 

Figure 5.2. Cumulative Change in Physical Ability with Age Among Masters Swimmers

• People who remain healthy and swim regularly can expect to be about as strong and agile at forty as they were at twenty-five. Sure, it takes commitment and self-discipline to maintain a consistent training program over many years. There is no question that it is harder to be physically fit at forty than at twenty-five. But the people who are so are not genetic freaks. They represent what all of us can achieve if we take the time and make the effort to maintain our bodies.

• Swimmers do not decline at the one-percent-per-year rate until they reach their early seventies. This is a dramatic finding. What it means is that if you live a sedentary life-style, you will lose 25 percent of your physical capacity by your fiftieth birthday. By age seventy-five, you will be half the person you were at twenty-five. In contrast, if you swim regularly the decline is only 3.5 percent by age fifty and 19.1 percent at seventy-five. For example, my study suggests that a seventy-year-old swimmer will have the strength and vitality of a normal forty-five-year-old. (See Figure 5.2.)

But the results away from the pool are far more significant than those in it. People who are physically fit are happier, healthier, and far more productive than those who are not.

Looking Ahead

I believe that the next few decades will witness a revolution in our understanding of the aging process. This study represents only a modest first step in learning how swimming affects the physical changes we normally associate with aging. I intend to continue the study over the course of my lifetime.

As dramatic as my results to date may be, however, I suspect that they understate what is theoretically possible. After all, most Masters swimmers have family and job responsibilities. They are unable to train more than an hour—or, at most, two hours—a day. Were they able to put in the time and mileage that top collegiate swimmers do, they probably could swim even faster.

But there is more to life than swimming. Most of us are happy to live in the real world of family, community, and career. What I find most heartening about the results of this study is that with a commitment to swim only an hour or so a day, a person can remain strong and vital until well into old age.