Work it!

Or in other words, get off your ass and get some exercise!

Physically active people have cells that look younger on a molecular level than those of couch potatoes, according to new research that offers a fundamental new clue into how exercise may help stave off aging.

The study, involving more than 2,400 British twins, found for the first time that exercise appears to slow the shriveling of the protective tips on bundles of genes inside cells, perhaps keeping frailty at bay.

"These data suggest that the act of exercising may actually protect the body against the aging process," said Tim D. Spector, a professor of genetic epidemiology at King's College in London who led the study, published yesterday in the Archives of Internal Medicine.

Telomeres cap the ends of chromosomes, the structures that carry genes. Every time a cell divides, the telomeres get shorter. When the telomeres get too short, the cell can no longer divide. Scientists believe that aging occurs as more and more cells reach the end of their telomeres and die -- muscles weaken, skin wrinkles, eyesight and hearing fade, organs fail, and thinking clouds.

The length of the twins' telomeres was directly related to their activity levels, the researchers found. People who did a moderate amount of exercise -- about 100 minutes a week of activity such as tennis, swimming or running -- had telomeres that on average looked like those of someone about five or six years younger than those who did the least -- about 16 minutes a week. Those who did the most -- doing about three hours a week of moderate to vigorous activity-- had telomeres that appeared to be about nine years younger than those who did the least.

Of course, medical researchers have long told us that exercise can stave off disease. The rationale has been that exercise has macro effects on the body that prevent disease, like strengthening the heart, or reducing insulin resistance, for example. But this appears to be the first large study to document the ways in which exercise can produce change on the cellular level which might actually lengthen the life of cells in our body. So the lesson is clear: eat and drink plenty of garlic and resveratrol, get lots of exercise, and quit eating so much meat, and who knows how long you might hang around?