NY Times - Excercise and Masters Athletes

.....EXERCISE HAS BEEN shown to add between six and seven years to a life span (and improve the quality of life in countless ways). Any doctor who didn’t recommend exercise would be immediately suspect. But for most seniors, that prescription is likely to be something like a daily walk or Aquafit. It’s not quarter-mile timed intervals or lung-busting fartleks. There’s more than a little suffering in the difference.

Here, though, is the radical proposition that’s starting to gain currency among researchers studying masters athletes: what if intense training does something that allows the body to regenerate itself? Two recent studies involving middle-aged runners suggest that the serious mileage they were putting in, over years and years, had protected them at the chromosomal level. It appears that exercise may stimulate the production of telomerase, an enzyme that maintains and repairs the little caps on the ends of chromosomes that keep genetic information intact when cells divide. That may explain why older athletes aren’t just more cardiovascularly fit than their sedentary counterparts — they are more free of age-related illness in general.

Exactly how exercise affects older people is complicated. On one level, exercise is a flat-out insult to the body. Downhill running tears quadriceps muscles as reliably as an injection of snake venom. All kinds of free radicals and other toxins are let loose. But the damage also triggers the production of antioxidants that boost the health of the body generally. So when you see a track athlete who looks as if that last 1,500-meter race damn near killed him, you’re right. It might have made him stronger in the deal.

Exercise training helps stop muscle strength and endurance from slipping away. But it seems to also do something else, maintains Mark Tarnopolsky, a professor of pediatrics and medicine at McMaster University in Hamilton, Ontario (who also happens to be a top-ranked trail runner). Resistance exercise in particular seems to activate a muscle stem cell called a satellite cell. With the infusion of these squeaky-clean cells into the system, the mitochondria seem to rejuvenate. (The phenomenon has been called “gene shifting.”) If Tarnopolsky is right, exercise in older adults can roll back the odometer. After six months of twice weekly strength exercise training, he has shown, the biochemical, physiological and genetic signature of older muscle is “turned back” nearly 15 or 20 years......  more