Exercise to slow aging is most important for those aged 40 to 65

Almost any amount and type of physical activity may slow aging deep within our cells, a new study finds. And middle age may be a critical time to get the process rolling, at least by one common measure of cell aging.

Dating a cell’s age is tricky, because its biological and chronological ages rarely match. A cell could be relatively young in terms of how long it has existed but function slowly or erratically, as if elderly.

Today, many scientists have begun determining a cell’s biological age — meaning how well it functions and not how old it literally is — by measuring the length of its telomeres.

Researhers looked more broadly at the interactions of exercise and telomeres among a wide swath of Americans.

To do so, they turned to the immense trove of data generated by the ongoing National Health and Nutrition Examination Survey, for which tens of thousands of adults answer questions annually about their health, including their exercise habits, and complete an in-person health exam, providing a blood sample.

If a participant answered yes to any of those four questions, he or she earned a point from the researchers. So, someone who reported walking received a point. If he also ran, he earned another, and so on, for a maximum of four points.

The researchers then compared those tallies to each person’s telomere length.

And there were clear associations. For every point someone gained from any type of exercise, his or her risks of having unusually short telomeres declined significantly.

Specifically, someone who participated in a single activity, earning them a 1, was about 3 percent less likely to have very short telomeres than someone who didn’t exercise at all.

That risk declined more substantially if someone exercised more. People who reported two types of exercise were 24 percent less likely to have short telomeres; three types of exercise were 29 percent less likely; and those who had participated in all four types of activities were 59 percent less likely to have very short telomeres.

Interestingly, these associations were strongest among people between the ages of 40 and 65, the researchers found, suggesting that middle age may be a key time to begin or maintain an exercise program if you wish to keep telomeres from shrinking.

This study is purely associational, so cannot show whether exercise actually causes changes in telomere length, only that people who exercise have longer telomeres.

Medical Science Sports Exercise- Movement-Based Behaviors and Leukocyte Telomere Length among US Adults.