The Scientific American: More Activity=Slower Aging

Just listen for a minute: When researchers at King’s College in London examined the genetic markers of biological aging of some
2,400 twins, they found that a comparison of  the subjects who exercised the most (an
average of 199 minutes weekly) to those who worked out the least (a mere 16 minutes or less a week) suggested that the exercise mavens were on average as much as a decade biologically younger than the slackers. The Scientific American reports on the study, which focused on the length of telomeres, and which was published in Archives of Internal Medicine.  Sciam reports that the scientists speculate that stress, inflammation and oxidative stress
(cell damage caused by oxygen exposure) may be responsible for
shortened telomeres in physically inactive people.
Read more in the Scientific American.