"Nature takes care of you for about 40 or 50 years, which is the average reproductive span, but after that you are on borrowed time." --Dr. Carl. W. Trygtad, geriatrician and head of the Division of Urgent and Emergency Care at Scripps Clinic in La Jolla
Betty Yoshioka, 49, is a Los Angeles businesswoman doing everything within her power to avoid growing old. Three years ago she took up running--marathon running. And this year, she volunteered for a series of comprehensive physiological evaluations, part of a 20-year study at USC, to determine the effects of exercise on the aging human body.
Yoshioka is typical of a growing number of middle-aged individuals who never before have been serious athletes but who are, late in life, starting to train and compete in the hope of staving off the effects of age.
Most latecomers to--as well as the regulars in--the world of athletics assume that vigorous exercise and a restricted diet will make them look better, feel healthier and live longer.
They may be right. Preliminary results of studies at USC and at several other universities suggest precisely what exercise aficionados had hoped to hear: Fatigue, weight gain, memory loss and other problems associated with aging may not be normal but instead the unfortunate and avoidable side effects of a sedentary life style.
This is not to say that we do not grow old and wear down. We do, of course, and the medical profession has organized two new subspecialties--geriatrics and geriapsychiatry--to help patients cope with the physical and psychological problems of aging. Scientists have also been busy trying to understand the fundamentals of the aging process. How, for example, do individual cells change as they get old? Do they have to change? What happens to sex in the later years of life? Does it have to deteriorate?
Much of the attention on aging, however, has been focused neither on understanding the process nor curing its effects, but on actually preventing it from happening in the first place--or at least delaying it as long as humanly possible.
Many organizations, including the American Heart Assn. and the President's Council on Physical Fitness, advocate the virtues of exercise as a way to enhance well-being and prolong life. There are countless popular books on the subject of fitness and age: "Weight Training for the Over-35s," "Exercises for Non-Athletes Over Fifty-One; It's Never Too Late," "The Senior Citizen's 10-Minute-a-Day Fitness Plan."
But scientists, physicians and other health experts say that modern science knows surprisingly little about the effects of physical activity on middle-aged people--and almost nothing about the impact of exercise on the elderly.
"It is true that some important advances have been made in recent years in understanding the causes of premature death," says Dr. Ralph S. Paffenbarger Jr., a Stanford professor of medicine and one of the country's experts on exercise and aging.
"Studies have shown clearly that people who stop smoking reduce their risk of cardiovascular disease and their risk of lung cancer.
"Some evidence from life insurance companies suggests that people who lose weight can expect to extend their lives a bit . . . Recent studies have shown that if there is a change in the lipoprotein profile (that is, if people reduce the amount of cholesterol and fat in their diet), there are benefits . . . If there is a change in the blood pressure level, either by pharmacological means or diet or exercise or some combination, there is also likely to be an increase in longevity.
"But," Paffenbarger says, "there is no data at all on the effects of physical activity and age.
"What happens," he asks, "when old or middle-aged people get out of the easy chair and become active? What is the optimal type of activity? . . . What's the minimal amount of exercise? Are there hazardous levels of exercise? . . . These are questions for which we do not have answers--yet."
The idea that exercise increases longevity is not a new one. In antiquity, there was speculation that sport was good for the human body. In more recent times, exercise has come to be viewed as beneficial for the psyche as well as the physique. It also has been observed that former athletes live longer than nonathletes.
Yet, there have never been studies to control bias in these observations; the theories associating exercise and health have never been proved, notes John O. Holloszy, a professor of preventive medicine at Washington University in St. Louis. It is quite possible, for example, that whatever genetic or biochemical characteristics cause people to become athletes also may be at work in allowing them to live long lives.
In a comprehensive review of the scientific and medical literature on exercise and aging published in 1983, Holloszy issued this warning:
The "good press that the health benefits of exercise have received in recent years is based largely on emotional reactions . . . and on wishful thinking. . . ."