Exercising when you’re 40 may be the most important time to slow aging

Get moving.
Get moving.
Image: Reuters/David Mdzinarishvili
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We all know that exercise is critical to staying healthy and living longer. New research suggests that exercising after age 40, in whatever dose, may be the most critical time of all.

Paul Loprinzi and Jeremy Loenneke of the University of Mississippi, and Elizabeth Blackburn of the University of California, San Francisco (who was part of the team that won the Nobel prize for medicine in 2009) looked at data for around 6,500 adults aged between 20 and 84, based on their responses to the National Health and Nutrition Examination Survey.

The survey includes responses from thousands of adults to questions about their health, matched to blood samples from an annual exam. Those blood samples allowed the researchers to study the participants’ telomere length. Telomeres are the caps on the end of DNA strands that shorten with factors including age, illness, and obesity; telomere length has been associated with longevity.

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The researchers tested to see whether exercise was related to less telomere shrinkage.

It was linked, but only statistically significant for one age group: those between the ages of 40 and 65. With each additional category of exercise—walking, cycling, lifting weights, and the like—these subjects became less likely to be in the group with the shortest telomeres.

The study, published in the journal Medicine & Science in Sports & Exercise, has a few shortcomings: the exercise data is self-reported and the relationship is not causal—it is unclear whether exercise directly prevents telomeres from shrinking. Also, the research didn’t identify which kind of exercise, duration, or intensity, is best.

Nevertheless, the research identified a strong relationship between exercise and a genetic marker thought to affect aging, adding to the vast body of research on the subject. Another large study showed that those who exercised for 450 minutes per week, or a little more than an hour per day, were 39% less likely to die prematurely than people who never exercised.