By Mark Stibich, PhD
Updated September 07, 2016
We all know that exercise is good for us, but did you know that it can make you nine years younger? Even more interesting, researchers are beginning to understand exactly how exercise actually keeps you young.
The first problem, of course, is figuring out how to define “staying young” or “successful aging.” One way is to measure aging through your DNA … literally. At the tips of your chromosomes are your telomeres, which serve as protective caps for the genetic material in between.
Your telomeres are known to shorten as you age. In fact, it turns out that telomeres are one of the most important factors in aging. Young people’s telomeres generally are between 8,000 and 10,000 nucleotides long (nucleotides are the building blocks of your chromosomes), but old people may have as few as 5,000 nucleotides making up their telomeres.
In this 2008 study showing exercise can make you nine years younger, researchers compared telomeres’ length with exercise habits in sets of identical twins.
Make Your DNA Younger
More than 1,200 pairs of twins (mostly women) enrolled in the research project. Researchers looked at the impact of exercise on the length of telemeres in the twins’ white blood cells.
The study found longer telomeres were positively associated with more recreational exercise. This finding held after the researchers adjusted for age, sex, body mass index, smoking, socioeconomic status, and physical activity at work.
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The telomeres of the most active subjects were 200 nucleotides longer than those of the least active subjects. In otherwise identical twins who didn’t exercise the same amount (one twin worked out more often than the other), telomeres in the more active twins were about 88 nucleotides longer than those of their less active (but otherwise genetically identical) sisters or brothers.
Determining how exercise can make your DNA younger and healthier represents a huge new step in understanding how lifestyle play a role in aging.
What Exercise is Good For DNA?
Working up a sweat seems to be important. In the twin study, people who exercised vigorously at least three hours each week had longer telomeres and were nine years “younger” (as measured by their telomeres) than couch potatoes who did no exercise. This held true after accounting for other factors such as smoking, age, weight and activity level at work.
However, there are hints in other research that very vigorous activity may not be as beneficial, at least in men. A 2013 study that tracked Helsinki businessmen over nearly three decades (no women were included, unfortunately) and found that the group exercising moderately had longer telomeres than both those who exercised strenuously (including a few who were competitive athletes) and those who didn’t exercise much at all.
More research clearly is needed to determine how much exercise, and what types, make your telomeres the youngest.
This may differ in men and women.
So What If My Telomeres Are Short?
Although research into telomere length is a relatively new field, researchers believe that shortened telomeres can increase the risk of age-related diseases like high blood pressure, mental difficulties, cancer and more.
This is because as telomeres shorten, there is more stress on your body’s tissues to function correctly. Researchers believe that exercise helps reduce damage by free radicals, allowing your body to invest its resources in maintaining health instead of repairing damage.
The Bottom Line
Exercise helps you live healthier. You should exercise not just for your DNA, but also to feel good and experience all the benefits of exercise.
Cherkas LF et al. The Association Between Physical Activity in Leisure Time and Leukocyte Telomere Length. Archives of Internal Medicine. 2008;168(2):154-158.
Savela S et al. Physical activity in midlife and telomere length measured in old age. Experimental Gerontology. 2013 Jan;48(1):81-4.