Doing vigorous exercise on a regular basis appears to slow down the body's aging process, according to German scientists.
The researchers measured the length of telomeres - caps on the ends of chromosomes - in blood samples drawn from athletes as well as from relatively healthy folks who don't normally engage in a lot of strenuous physical activity.
The findings, published in the journal Circulation, showed that athletes tended to have longer telomeres than other people, indicating that the "biological clock" within their cells had essentially slowed down.
Telomeres are often compared with the plastic tips on the ends of shoelaces, preventing the chromosomes from fraying. Telomeres tend to get shorter as a cell undergoes normal division. Eventually the telomeres become so short they can no longer hold the chromosomes intact and the cell dies.
The new study indicates that long-term exercise appears to boost the activity of an enzyme called telomerase that protects telomeres from degradation, said the lead researcher, Ulrich Laufs at Saarland University. "It looks like the shortening of telomeres can be prevented, to some extent, in those individuals who engage in a high level of exercise."
Previous research has demonstrated that regular exercise is good for the heart and the cardiovascular system, and can help increase the odds of living a longer, healthier life. But much is still unknown about how exercise affects the body at the cellular level.