Exercise the Fountain of Youth?

IN a series of new studies prompted by the geriatric population explosion, researchers are finding that moderate exercise can not only retard the effects of aging but can actually reverse them.

Proper exercise, appropriately and carefully pursued throughout life - even into the 80's and beyond, when the body was once regarded as too weak and frail for such activity - has been shown in scores of studies to significantly deter the deterioration of bodily functions that traditionally accompany aging.

Among the demonstrated benefits are increased work capacity, improved heart and respiratory function, lower blood pressure, increased muscle strength, denser bones, greater flexibility, quicker reaction times, clearer thinking and reduced susceptibility to depression.

The research has demonstrated, as one investigator put it, that disuse accounts for about half the functional decline that usually occurs between the ages of 30 and 70. Just as three weeks of complete bed rest results in losses equal to 30 years of aging, exercise by middle-aged and elderly people can set the clock back by as many as 25 to 45 years, the studies have shown.

Furthermore, the findings show that no matter when in life a person starts to exercise, improvements in functioning can occur.

Dr. Roy J. Shephard, an expert on exercise and aging at the University of Toronto, concluded: "You'd have to go a long way to find something as good as exercise as a fountain of youth. And you don't have to run marathons to reap the benefits. For the average older person who does little more than rapid walking for 30 minutes at a time three or four times a week, it can provide 10 years of rejuvenation."

The findings contradict the long-standing and widespread belief that the elderly cannot improve physiologically and at best may only slow their decline. They also demonstrate that sometimes remarkable athletic achievements by the elderly are not solely determined by "good genes" but also result from "taking care of the genes they have through continued activity that promotes fitness," according to Dr. Herbert A. deVries, a pioneer in the field.

"Older people, even those over 70 or 80, can make as great a percentage gain as the young," said Dr. deVries, who recently retired as director of the Andrus Gerontology Center at the University of Southern California.

In one of Dr. deVries's earliest studies, more than 200 men and women aged 56 to 87 who lived in a California retirement community participated in a fitness program that included a walk-jog routine, calisthenics and stretching for one hour a day three to five times a week. After just six weeks, "dramatic changes" were seen, Dr. deVries said: Blood pressure dropped, percentage of body fat decreased, maximum oxygen capacity increased, arm strength improved and muscular signs of nervous tension diminished. Peak fitness occurred after 18 to 42 weeks.

"Men and women of 60 and 70 became as fit and energetic as those 20 to 30 years younger," Dr. deVries noted in his book "Fitness After 50" (Charles Scribner's Sons). "The ones who improved the most were the ones who had been least active and most out of shape."

No 'Fountain of Youth'

However, even one of activity's staunchest advocates, Dr. Everett L. Smith, director of the Biogerontology Laboratory at the University of Wisconsin, readily concedes: "Exercise is not an unending fountain of youth. Eventually we all decline. But the quality of life is so much higher for the elderly who are physically active than for people who sit in a rocking chair waiting for the Grim Reaper."

Dr. Smith has shown, for example, that among once-sedentary women in their 50's who participated in an aerobic dance program for six years, fitness improved by 23 percent and they experienced none of the functional declines typically seen with increasing age.

Of course, exercise by the elderly is not without risk. Dr. Charles Godfrey, a Toronto specialist in rehabilitation medicine, said, "The prospect of people over 60 starting to jog freezes my blood vessels."

Dr. Godfrey, who has seen more than his share of the fallout from overambitious exercise programs, advises against jumping and pounding exercises for people over 50 because, he said, "they have produced an epidemic of self-inflicted injuries." Nonetheless, Dr. Godfrey insisted that "exercise is the only way to go, so long as it is done properly."

Some Pleasure, Too

In addition to the health value of exercise, experts urge consideration of its pleasurable aspects. According to Dr. Shephard: "Telling a healthy 75-year-old that 'at your age, you ought to be careful' can result in a very boring existence. There's not much point in staying home and being careful if you'd rather be out enjoying yourself on the tennis court."

The functional declines that typically accompany advancing age are often dramatic and depressing. With each year after reaching maturity, the heart's ability to pump blood declines by about 1 percent. By middle-age, blood vessels are 29 percent narrower. By age 60, blood flow from the arms to the legs is 30 to 60 percent slower than at age 25. The amount of air a person can exhale after a deep breath lessens and the chest wall stiffens with age, resulting in a decline in the amount of oxygen the body can use of 50 percent in men and 29 percent in women by age 75. The number of muscle fibers decreases at a rate of 3 to 5 percent a decade after age 30, leading to a 10 to 30 percent loss of muscle power by age 60. The lost muscle is usually replaced by body fat, and results in a 10 percent lowering of the basal metabolic rate (or caloric need at rest) by age 70. The speed at which nerve messages travel drops 10 to 15 percent by age 70, flexibility declines 20 to 30 percent, and bone losses average 15 to 20 percent in men and 25 to 30 percent in women.

The recent studies have shown, however, that all of these age-associated declines can be delayed by fitness-promoting exercise.

Among the most telling findings are these:

* Dr. deVries showed that in men who averaged 70 years of age, a physical conditioning program improved by 35 percent their physical work capacity - as measured by the amount of oxygen their bodies used during maximum exercise - and increased by 29 percent the amount of oxygen transported to cells. "This translates into greater vim, vigor and vitality," observed the 68-year-old exercise physiologist, who has found that a trained 65-year-old can have a better physical work capacity than a sedentary 35-year-old.

* In various studies both here and abroad, participation in exercise programs by older people has been shown to lower their resting heart rate (the number of times the heart beats per minute), increase their heart's stroke volume (the amount of blood pumped with each beat), reduce the tendency of their blood to form clots, lower their blood pressure and increase the proportion of artery-protecting HDL-cholesterol in the blood.

* Using strength-training exercises for eight weeks among older people, Toshio Moritani, a researcher in Dr. deVries's laboratory, showed that the elderly could gain as much muscle power, when measured as a percentage increase, as young people could.

* In a 12-week study of exercises to promote flexibility, Kathleen Munns of the Biogerontology Laboratory at the University of Wisconsin showed that the 20 participants whose average age was 72 were able to increase the range of motion in their necks by 28 percent, in the wrists by 13 percent, in their shoulders by 8 percent, in their hips and back by 27 percent, in their knees by 12 percent and in their ankles by 48 percent.

* At the same laboratory, Dr. Smith compared bone losses among women in their 80's who lived in a nursing home. In the 12 women who did chair exercises for 30 minutes three times a week for three years, bone mineral increased 2.29 percent, whereas in a similar group of inactive women, bone loss averaged 3.28 percent. This and other studies have shown that at any age, when stress is placed on bones through exercise, their calcium content and resistance to fracture are increased.

* The tranquilizing effects of exercise also are accessible at any age. Dr. deVries tested the startle response to a mild electric shock by 10 elderly people, some as old as 83. After exercise, the response decreased by an average of 18 percent.

* In another study at Purdue among previously sedentary middle-aged men who took part in a four-month fitness program, a significant improvement was noted in the mental processes controlled by the brain's left hemisphere, the part responsible for logical reasoning and mathematics. The 24 men who exercised for about one and a half hours a day three times a week were compared on 10 tests of mental ability to a similar group of men who remained sedentary.

Dr. Raymond Harris, who heads the Center for the Study of Aging at Albany Medical College, noted that when nerve cells are deprived of stimuli they atrophy, suggesting that stimulation of the central nervous system by physical activity may retard the loss of nerve cells in the brain and elsewhere. Indeed, aerobic exercise has been shown to enhance blood flow to various parts of the brain as well as to increase the speed with which nerve messages travel through the brain.