The long-observed association between exercise and a slightly longer life span may have its origins in DNA maintenance, a new study finds. Researchers report that the ends of chromosomes hold up better in active people than in sedentary individuals, possibly extending cell life and contributing to overall survival.
Those ends, called telomeres, consist of repeating DNA segments that guard the ends of chromosomes much as plastic tips preserve shoelaces. Telomeres keep chromosomes from degrading or forming aberrant bonds with other chromosomes, but they shorten each time a cell divides. While there is a raging scientific debate over the possible connection between truncated telomeres and aging, it's known that shrinking them to a critically short length can mean the death of a cell.
Since regular exercise is known to add a few years on average to the typical person's life span, Tim Spector, a physician and epidemiologist at King's College London, and his colleagues set ou