The study involved 63 women, ages 54 to 82, all healthy. The women were divided into either a sedentary or an exercise group. In the exercise group, vigorous exercise was defined as that which increased heart rate and sweating. I assume that sexual activity was excluded in this rather wide-ranging definition. In any case, the study focused on the effects of stress and exercise on telomeres. Telomeres are caps on the ends of cell chromosomes that maintain chromosome stability and promote cellular repair. Each time a cell divides, telomeres shorten. When they shorten to a certain extent, the cell stops dividing and dies. As such, telomere measurement, usually in white blood cells, is often used as an index of longevity. Prematurely shortened telomeres are linked to the onset of cardiovascular disease and diabetes. Having high blood pressure, as well as constantly being exposed to factors that increase stress, can prematurely shorten telomeres. In contrast, exercise has been shown to blunt telomere shortening. One way it does this is by modifying oxidative stress, which shortens telomeres. But overtraining is known to increase stress to the extent that the benefical effects of exercise on maintaining telomere length is blunted. As such, exercising too much may hasten mortality.
The new study of older women showed that as little as 40 minutes of exercise spread over three days was enough to provide beneficial telomere protection, even when the women are exposed to stress. On the other hand, in women who were also exposed to stress, but didn't exercise, the telomeres weren't protected, and shortening occurred.Exercise thus blocks the negative effects of perceived stress on telomere length. Exercise may also help in this regard through promoting the activity of telomerase, an enzyme that maintains telomeres. In fact, cancer cells are considered immortal because they produce telomerase, which allows them to keep dividing interminably. Some antiaging advocates have proposed that supplying telomerase to older people may provide antiaging effects. But it could also promote cancer. The effects of exercise,however, are safe and this study shows another way that exercise probably helps extend longevity and maintain health through the years by helping to control the harmful effects of stress on the body and the mind.
Puterman E, et al. The power of exercise: Buffering tghe effect of chronic stress on telomere length.Plos One 2010; in press.
