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Intense Activity Keeps Telomeres Long

Dec. 1, 2009 -- People who exercise regularly tend to stay healthier as they age, and now new research may explain why at a cellular level.

Compared to people who did not exercise, elite runners in the study had cells that looked much younger under a microscope.

Specifically, investigators measured the length of telomeres -- the DNA on either end of thread-like chromosomes.

Just as the plastic tips on the ends of shoelaces keep the laces from fraying, telomeres protect the chromosomes that carry genes during cell division.

Each time a cell divides, telomeres get shorter. When telomeres get too short, cells can no longer divide and they die.

Researchers now believe telomere shortening is critical to aging, making people more vulnerable to diseases such as heart disease, diabetes, and cancer.

“Telomeres can be thought of as a biological clock,” lead researcher Ulrich Laufs, MD, of Homburg, Germany’s Saarland University tells WebMD. “If they are shorter than a critical length, the process of programmed cell death starts.”

Exercise and Telomeres

The new research involved animal and human studies designed to determine how exercise impacts telomere length.

In the animal studies, mice that ran on a running wheel for as little as three weeks showed evidence of increased production of telomere-stabilizing proteins, which protected against cell death.

In the human studies, middle-aged professional athletes who ran about 50 miles a week and had done so for many years had longer telomeres than healthy, age-matched non-athletes who did not exercise regularly.

Not surprisingly, the athletes also had slower resting heart rates, lower blood pressures, and less body fat.

The study appears in the Dec. 15 issue of the American Heart Association journal Circulation.

“This is the first time it has been shown at the molecular level that exercising has an antiaging effect on the cardiovascular system,” Laufs says.

American Heart Association spokesman Barry Franklin, PhD, calls the new research "phenomenal."

“In many respects, I think this is a blockbuster study that complements research in twins published last year,” he tells WebMD.

Exercise May Trump Genes

That study suggested exercise might trump genes when it comes to keeping people young.

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