Greater Good

Chances are, you already know exercise is good for you. But in case you need more than a New Year's resolution to get back in the habit, a study published this week in the Archives of Internal Medicine provides yet another motivator. Among adults who exercise the most (around three hours a week), a key indicator of cellular aging resembles that of more sedentary individuals 10 years their junior.

Researchers at King's College in London took blood samples from just over 2400 twins, and measured telomere length as an indicator of cellular aging. Telomeres are DNA/protein complexes at the tips of chromosomes that serve as a record of how many times a cell has divided. Each time a chromosome is copied, the telomeres capping the ends shorten, as the cellular machinery cannot copy the DNA to the very end. After a certain critical threshold, short telomeres serve as a signal that the cell should no longer divide. But telomeric age does not correlate precisely with chronological age. Life experiences such as chronic stress, smoking, and high BMI can all take their toll on telomere length. Other experiences, such as frequent exercise, may be protective.

Reduced cellular aging can't promise an increased lifespan, which depends on many factors. But regular exercise does increase your life expectancy by about three years, and in the meantime, more youthful cells don't sound half bad!