Update: The winter 1992 issue of Sports Science Exchange (from the Gatorade Sports Science Institute) reported questions and answers from a round-table discussion with four scientists who study the physiological effects of exercise and nutrition in the elderly. I thought it might be interesting to summarize some of the discussion from this roundtable:
Is an individual ever too old to embark on an exercise program? All of the scientists agreed that chronological age is less important than physiologic age. Some elderly people may require medical supervision when they exercise, but favorable adaptations to exercise occur in people who have been sedentary for as long as 40 years. One researcher mentioned people who in their 90s made significant strength and performance gains when placed on a weight-training program. Some of them who were confined to wheelchairs were able to get up and walk after participating for several months, and all of this older group were able to function better after training. If there is any question about health, older individuals should receive medical clearance; but, exercise can be beneficial at any age.Can elderly persons expect to see the same physiological adaptions as younger persons when they begin an exercise program? Most of these scientists felt that the adaptive capacity of healthy, older persons was very similar to that of younger persons. The change in aerobic capacity is somewhere in the neighborhood of 20 to 30 percent in older people, but there appears to be a difference in the way the adaptation occurs. In younger subjects, there is usually an increase in the amount of blood the heart can pump as well as a change in the amount of oxygen the muscles can use; in older persons, especially women, the changes seem to be mostly in the muscles, with little change in cardiac function.
Strength training not only increases strength in older people, it also changes the ability of muscles to process protein and stimulates muscle hypertrophy - just like in younger persons - but not always to the same extent. Also, fit, elderly subjects are able to retain the ability to adapt to extremes in environmental conditions, particularly high heat and humidity, despite age-related changes in sweat- gland function and control of skin blood flow.
At what age do individuals reach their peak physiological capabilities? People in their 20s tend to attain the best times in endurance events, but peak aerobic performance is somewhat event specific. For instance, many swimmers do best in their teens and early 20s. On the other hand, Carlos Lopes won the Olympic marathon in 1984 when he was in his late 30s.
Muscular strength typically increases up to around age 30 and then plateaus until about age 50 and then begins to decline. The important point is that, regardless of how old you are, you can strive to be the best that you can be for your age and ability.
I'll continue this review next week.
Garth Fisher is director of the Human Performance Research Center at Brigham Young University.