The physiology of aging as it relates to sports

AMAA Journal, Summer, 2004 by Edward H. Nessel

All graphs, charts and tables were reproduced with permission from The McGraw-Hill Companies and excerpted from Jack H. Wilmore and David L. Costill, Physiology of Sport and Exercise, 2nd edition, 1999, McGraw-Hill.

Overview

Athletes today of all ages and abilities are on a quest for optimum performance and in that quest, age often becomes secondary. Opportunities are more evident now than ever before for older athletes to compete in various sports activities, both within an age bracket and in open competition. But even the most highly-trained older person experiences a decline in performance after the fourth or fifth decade of life (1).

We can readily agree that repeated vigorous activity is extremely important to maintaining robust health into advanced age; however, there are differences in physiologic parameters that occur with the aging process. Even at a high level of condition, the older athlete simply requires more recovery time than a younger athlete to engage in a repeat maximum effort.

Of course, there is another vital variable that should be addressed regarding one's overall potential. That element is simple genetics. "Picking the right parents" and being the recipient of a great mix of DNA can influence up to 50% of an athlete's ability to perform at a superior level (2). But how much of that ability is maintained throughout the years directly varies according to how much vigorous exercise is performed during later years in life.

[FIGURE A OMITTED]

The following parameters will be discussed and illustrated: sports performance comparisons by age; respiratory, cardiovascular, strength and body composition changes with aging; trainability of the older athlete and how training can delay decline in exercise performance.

Sports Performance

Records in running, swimming, cycling and weight lifting suggest that our physical prime comes during our 20s or early 30s. Although older runners have achieved exceptional records, running performance generally declines with age and the rate of this decline appears to be independent of distance. Longitudinal studies of elite distance runners indicate that despite a high level of training, performance in events from the mile to the marathon declines at a rate of about 1% per year from the age of 27 to 47 years (3, 4). In a cross-sectional analysis, American records for both the 100m and 10km runs also decrease by about 1% per year from age 25 to 60. Beyond age 60, however, the records for men slow by nearly 2% per year. Another cross-sectional sprint-running test of 560 women between the ages of 30 and 70 revealed a steady decline in running velocity of 8.5% per decade (0.85% per year). The patterns of change are about the same in both sprint and endurance running performances (see Figure A).

A study of past national Masters swimming championships (1991-1995) shows that for the 1500m freestyle, both men and women slowed steadily from age 35 to about 70. After age 70, swimming times slowed at even a faster rate. Furthermore, the rate and magnitude of the declines in both the 50m and 1500m freestyles were greater for females than males (5). Another analysis (see Figure B) shows a comparison of U.S. Masters swimming records in the 100m freestyle; the times get slower by about 1% per year for both men and women from age 25 to age 75. Interestingly, though, because success in this sport depends on skill as well as on strength and endurance, some U.S. Masters swimmers have reached their personal best performances from ages 45 to 50.

Optimal cycling performances are typically seen between the ages of 25 to 35. Male and female cyclists' records (for the 40km) drop at about the same rate with age--an average of 20 seconds (0.6%) per year. The U.S. national cycling records for the 20km distance demonstrate a similar pattern for both sexes. For this distance, speed decreases by about 12 seconds (0.7%) per year from age 20 to nearly age 65 (6).

In general, maximal muscle strength peaks between the ages of 25 and 35. Beyond that age range, the ability to lift weight declines at a steady rate of about 1.8% per year. Of course, as with other measurements of human performance, individual strength varies considerably.

What then are the specific parameters which cause inevitable declines in athletic performance?

Changes in Cardiorespiratory Endurance with Aging

To a large extent, changes in endurance performance that accompany aging are caused by decrements in both central and peripheral circulation. Measurements of cardiac output and limb blood flow are not easily performed and, therefore, early studies of the effects of aging on the physiology of endurance exercise examined maximum oxygen uptake (VO2max). This is a parameter that closely parallels maximal cardiac output (see Table 1). More recently there have been efforts to measure blood flow and oxygen exchange in the leg muscles of exercising older subjects; however, these studies are limited in number.

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Studies of Normally Active People