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.
Short leukocyte telomere length (LTL) has become a hallmark characteristic of aging. Some, but not all, evidence suggests that physical activity (PA) may play an important role in attenuating age-related diseases and may provide a protective effect for telomeres. The purpose of this study was to examine the association between PA and LTL in a national sample of US adults from the National Health and Nutrition Examination Survey.
National Health and Nutrition Examination Survey data from 1999 to 2002 (n = 6503; 20-84 yr) were used. Four self-report questions related to movement-based behaviors (MBB) were assessed. The four MBB included whether individuals participated in moderate-intensity PA, vigorous-intensity PA, walking/cycling for transportation, and muscle-strengthening activities. An MBB index variable was created by summing the number of MBB an individual engaged in (range, 0-4).
A clear dose-response relation was observed between MBB and LTL; across the LTL tertiles, respectively, the mean numbers of MBB were 1.18, 1.44, and 1.54. After adjustments (including age) and compared with those engaging in 0 MBB, those engaging in 1, 2, 3, and 4 MBB, respectively, had a 3% (P = 0.84), 24% (P = 0.02), 29% (P = 0.04), and 52% (P = 0.004) reduced odds of being in the lowest (vs highest) tertile of LTL; MBB was not associated with being in the middle (vs highest) tertile of LTL.
Greater engagement in MBB (movement based behaviors -aka exercise) was associated with reduced odds of being in the lowest LTL tertile.