Extra Years for Extra Effort

As editor of Harvard Magazine, John Bethell, 53, spends much of his working day sitting in front of a word processor. He had not been very active out of the office either until, sometime around his 40th birthday, he decided to work on conserving "what physical health I had and even to improve on it, if it wasn't too late." Now he takes stairs two or three at a time, skis whenever he can and runs 20 to 30 miles a week, often jogging his five final commuter miles from Boston's North Station to his office near Harvard Square. On weekends he competes in 10-km road races and regularly finishes among the top three or four runners in his age group. "That feeds my self-esteem," says Bethell, who maintains a lean 5-ft. 11-in., 160-lb. silhouette. Even more satisfying, he feels that he is healthier today than he was in his 30s.

He is probably right, according to a continuing study of nearly 17,000 of his fellow Harvard alumni. The report, published last week in the New England Journal of Medicine, demonstrates scientifically what for health enthusiasts has long been an article of faith: regular exercise can indeed prolong life. "People who are active and fit can expect to live a year or so longer than their sedentary counterparts," says the report's principal author, Dr. Ralph Paffenbarger Jr. of the Stanford University School of Medicine. "For each hour of physical activity, you can expect to live that hour over -- and live one or two more hours to boot."

The study, the most comprehensive ever to relate exercise and longevity, tracked the health and life-styles of 16,936 men who entered Harvard from 1916 to 1950. The subjects were followed until 1978, by which time 1,413 had died. Correlating death rates with exercise habits, the researchers were able to quantify, for the first time, the relationship between various amounts of physical activity and length of life.

Regular exercise, the researchers found, is a critical factor in determining longevity. Men who walked nine or more miles a week (burning off at least 900 calories), for example, had a risk of death 21% lower than those who walked less than three miles a week. The optimum expenditure of energy seems to be about 3,500 calories a week, the equivalent of six to eight hours of strenuous bicycling or singles tennis. The Harvard men who worked out that much had half the risk of death of those who did little or no exercise. Moreover, the study showed that a lifetime habit of engaging in energetic activity three to four times a week could reduce the negative health effects of cigarette smoking or high blood pressure. It even partly offset an inherited tendency toward early death.

Paffenbarger and his colleagues have used the Harvard sample, which is relatively easy to keep track of, for various health-related studies. But they caution against applying the results too specifically to the general population. The alumni group, for example, includes no women and is primarily white. Further, in terms of intelligence and affluence, "the bulk of these men are cut from the same cloth," says Paffenbarger. "In general, they live longer than the average Caucasian American of comparable age." On the other hand, somewhat surprisingly, the rate of suicide among the Harvard graduates was 50% higher than that of the overall population.

There were other surprises. Men who played vigorous sports like squash and full-court basketball to excess -- burning more than 3,500 calories a week -- went past the point of positive returns and had higher death rates than their more moderate colleagues. Equally unexpected was the finding that those who had put on at least 15 lbs. since graduation lived longer than alumni who had gained less; the researchers speculate this may have been because some of the latter suffered from wasting diseases. And the risk of death was high for former varsity athletes who stayed unusually active or slacked off dramatically. Says the report: "Evidently, inheritance of a sturdy constitution (as implied by varsity athletic status) is less important to longevity than continuation of adequate lifetime exercise."

To the inveterate couch potato, the average year or two gained by serious exercisers may seem small compensation for a lifetime of pedaling an exercise bicycle. But in individual terms, the researchers note, such an increase can . be significant, since it means that the lives of some men would presumably be extended ten to 20 years. In fact, the steady benefits of exercise are comparable to those that come from medical breakthroughs. Paffenbarger makes the point by projecting the impact of curing the disease most feared by Americans. "If it were possible to eliminate cancer as a cause of death," he says, "the years of life gained would be about the same."

In the Journal of the American Medical Association last week, two more reports further underscored the health benefits of exercise, specifically for runners. "It's an old story that running wears out joints," says Dr. Nancy Lane, who directed a Stanford study comparing the joints of 41 long-distance runners with those of 41 nonrunners and occasional runners. The researchers found no difference between the two groups in the prevalence of osteoarthritis, or degenerative joint disease. However, the runners, ages 50 to 72, did have 40% higher bone density than their counterparts in the control group. "Running prevents bone loss," concludes Lane, "and that's a good finding for women," since they often develop osteoporosis after menopause. At the University of Florida, Gainesville, Dr. Richard Panush and his colleagues compared a group of 17 male runners, ages 50 to 74, with a similar group of 18 non runners and, like the Stanford team, turned up no significant differences in the incidence of joint disease. "Our results are consistent with the thought that putting a normal joint through the normal range of motion is not harmful," says Panush. "Running may include pounding and wear and tear, but it does not necessarily cause arthritis."

By Philip Elmer-DeWitt. Reported by Cristina Garcia/San Francisco and Suzanne Wymelenberg/Boston