Wednesday, December 15, 2010

Turning back aging - The 91 year old athlete

I've been meaning to pass on some nuggets from an NYTimes Magazine article by Bruce Grierson, which tells the story of Olga Kotelko, a remarkable 91 year old woman who has shattered many world records in her Masters Competition age group. He references a number of studies and observations on aging that I was unaware of, particularly mentioning muscle physiologist Tanja Taivassalo. This first quote below gave me a bit of pause (since I am 68 years old, and in extremely good shape)...
We start losing wind in our 40s and muscle tone in our 50s. Things go downhill slowly until around age 75, when something alarming tends to happen...“There’s a slide I show in my physical-activity-and-aging class,” Taivassalo says. “You see a shirtless fellow holding barbells, but I cover his face. I ask the students how old they think he is. I mean, he could be 25. He’s just ripped. Turns out he’s 67. And then in the next slide there’s the same man at 78, in the same pose. It’s very clear he’s lost almost half of his muscle mass, even though he’s continued to work out. So there’s something going on.” But no one knows exactly what. Muscle fibers ought in theory to keep responding to training. But they don’t. Something is applying the brakes.
This seems not to be happening in Olga Kotelko, and a number of studies are looking at processes that seem to stall the natural processes of aging.
Exercise has been shown to add between six and seven years to a life span...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.

Mark Tarnopolsky (professor of pediatrics and medicine at McMaster University in Hamilton) maintains that 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 this is right, exercise in older adults can roll back the odometer. After six months of twice weekly strength exercise training, Tarnopolsky has shown that the biochemical, physiological and genetic signature of older muscle is “turned back” nearly 15 or 20 years.

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