Steincrohn’s thesis was that the heart needed rest, not exercise, to stay healthy. Therefore, on reaching middle age it was best to avoid all exertion beyond that necessary for conducting the business of life. “Don’t lift a finger unnecessarily after forty” was Steincrohn’s motto. “Bending over to tie and untie your shoes; bringing the fork to your mouth; the rubdown after a shower; laughing; talking and reading—all these furnish your daily exercise requirements.” Steincrohn, then in his forties, made clear that he had managed to shake the exercise habit completely, but for those who insisted on continuing to play a bit of golf, he advised dawdling on the course and taking a break for a smoke and a drink between nines. As for old codgers of fifty who persisted in playing tennis, he had nothing but reproach—”infantile exhibitionism.”

Steincrohn reiterated his antiexercise arguments, only slightly hedged, in a 1968 book, but by then even he conceded that the tide of medical opinion had turned against him. A major force behind that change was Paul Dudley White, the cardiologist. In the 1930’s White had become convinced that exercise to the point of pleasant fatigue—long bicycle rides were his favorite form—benefited the heart. When he came into the public eye after being summoned to treat President Dwight Eisenhower following his heart attack in 1955, White made use of his new prominence to promote the cause of exercise through speeches, articles, and interviews. Dr. White, who died in 1973 at the age of eighty-seven, was a dogged exerciser himself, pedaling his bicycle thirty miles a day even in his later years.

In the sixties and seventies White was joined in his crusade by many other physicians and medical researchers. Their central message was that the most valuable exercise for general health was activity that forced the respiratory and circulatory systems to work hard for prolonged periods. Far from draining the organism of vitality, such, exercise was said to increase the efficiency of the heart and to expand its capability. The exercise needed to achieve this effect involves considerable effort; there is no such thing as effortless exercise. A typical program might call, for example, for jogging as long as an hour several times a week, or perhaps for sustained stints of cycling or swimming. Most Americans still don’t exercise much, of course, and many are still overweight, but, as the jogging craze in particular illustrates, millions have heeded the message. And their ranks include many well along in years. “Age is not a major obstacle to fitness,” insists Dr. Kenneth H. Cooper. As the developer of the widely followed “aerobics” system, Cooper is more responsible than anyone else for starting Americans jogging.

It is conceivable that the new experts are wrong. But the assumption has to be that the march of medical science is generally onward and upward and that the exercise advocates know what they’re talking about. Moreover, they are beginning to gather some statistical evidence that backs them up. A report issued in 1977 on a study of seventeen thousand men who enrolled at Harvard between 1916 and 1950 concluded that those who habitually exercised intensively suffered markedly fewer heart attacks than those who didn’t. Similar reports are not yet available on women, and indeed one recent medical study of top women athletes such as Olympics trainees revealed the curious fact that a prolonged program of heavy exercise temporarily makes some women stop menstruating. There seems to be every reason to think, however, that the beneficial results of regular, energetic exercise are not confined to males.

Then, too, there is the subjective evidence of those who have found that they don’t have to put aside games at forty and who derive deep satisfaction from the discovery that stamina can even grow with age. We are learning that we are not as delicate as was once thought and that we do not need to coddle ourselves, slow our step, and consign the tennis racket to the back of the closet shelf just because we are no longer young. In short, we are developing a whole new attitude toward growing old. And we can only feel sorry for all those who in the past were made to feel old before their time by the misguided fitness “experts” and the sedentary doctors.