New study suggests exercise promotes successful aging
by Tucson Citizen on Mar. 31, 2008, under Body
Does regular exercise promote successful aging? To many of us, that means does it add more years to your life? Exercisers say yes; the sedentary say no. Who’s right?
Hard to say because the impact of exercise on aging is complicated by heredity.
If you did a good job of picking parents who come from folks who live long lives, you probably will follow suit. You are preprogrammed genetically for a long life.
Will you live longer if you exercise regularly? Hard to say. Will you live a shorter life if you don’t exercise? Probably.
Research suggests that even if you are preprogrammed for a long life, being sedentary increases the odds that you will die before your time. You still may live a long life if you have good genes, but if you are preprogrammed to hit 90 and die at 82, it’s before your time.
To further complicate matters, our modern drugs and medical interventions may keep you alive longer even if you are sedentary.
But you may be severely compromised in the latter stages due to severe weakness or worse because of chronic diseases like heart disease, stroke, diabetes or cancer.
My argument is exercise adds life to your years, even if it doesn’t add years to your life.
New research
A new study published in the Archives of Internal Medicine takes on the topics of exercise and aging. In an effort to control the influence of heredity, researchers studied more than 2,000 adult identical twins. The lifestyles of all participants were examined with regard to exercise habits, smoking, obesity, socio-economic status and amount of “on the job” physical activity.
In all subjects, as they got older there was a progressive loss of length in the telomeres, reflecting the aging process. But subjects who were more physically active had longer telomeres than their sedentary twin counterparts.
The researchers also collected DNA samples and measured the length of telomeres. Telomeres are at the ends of chromosomes, like the plastic cap on the end of a shoelace.
Telomeres are known to shorten over one’s life span. Many researchers believe they can serve as a marker of biologic aging. In other words, the shorter your telomeres, the older your biologic age – the more wear and tear your body has endured.
Since identical twins were studied, it seems reasonable to assume that at birth telomere length was the same. This suggests that if one twin has shorter telomeres, it must be lifestyle influences, rather than genetic predisposition.
Physically active twins were compared with the least active twins. The results were striking.
Twins who were physically active at least 199 minutes per week (approximately one half-hour per day) were compared with twins who were least active and averaged only 16 minutes of physical activity per week. That’s about 2.5 minutes a day – a trip to the mailbox, then back to the recliner.
That’s amazingly sedentary by any standard, and it appears to be taking quite a toll, as the telomere length of the nonexercisers was found to be substantially shorter. More importantly, the length of telomeres in the physically active twins was comparable to folks at least 10 years younger.
Stress reduction
If exercise helps reduce biologic aging as reflected in telomere length, what is the possible mechanism at work? Researchers suggest it might be stress reduction.
It has been shown that stress decreases telomere length and exercise reduces stress. But exercise is only one means of reducing stress.
Therefore, if these relationships are found to be valid, it’s possible that meditation, prayer and other stress-reducing practices, as well as daily exercise, may help promote longevity.
The bottom line is, regardless of how it works, it appears exercise may influence biologic aging in a positive way. According to this research, something as simple as a daily 30-minute walk may help your body stay 10 years younger than your age would suggest.
Bryant Stamford is professor and chairman of the department of exercise science at Hanover College in Hanover, Ind. Address questions or suggestions to “The Body Shop,” The Courier-Journal, P.O. Box 740031, Louisville, Ky. 40201-7431
