How Exercise May Slow Your Biological Aging


Getty Images / Thomas Barwick

We all know that exercise is good for us, but did you know that it can help your body function as if it were 10 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". 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 older people may have as few as 5,000 nucleotides making up their telomeres.

Make Your DNA Younger

One 2008 study showed how exercise can slow your biological aging by up to 10 years. In the study, researchers compared telomeres' length with exercise habits in sets of identical twins.

More than 1,200 pairs of twins (mostly white women) enrolled in the research project. Researchers looked at the impact of exercise on the length of telomeres 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.

Body Mass Index (BMI) is a dated, biased measure that doesn’t account for several factors, such as body composition, ethnicity, race, gender, and age. 


Despite being a flawed measure, BMI is widely used today in the medical community because it is an inexpensive and quick method for analyzing potential health status and outcomes.

The telomeres of the most active subjects were 200 nucleotides longer than those of the least active subjects. In 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 keep your DNA "young" represents a huge new step in understanding how lifestyle can 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 10 years "younger" (as measured by their telomeres) than people who did not exercise regularly. 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 is needed to determine how much and what type of exercise promotes younger telomeres, as well as whether men and women would have different recommendations.

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, your DNA has less of a "buffer", and so any damage it receives is more likely to affect cellular functioning. Researchers believe that exercise helps reduce damage from free radicals, allowing your body to invest its resources in maintaining health instead of repairing damage.

A Word From Verywell

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.

4 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Cherkas LF, Hunkin JL, Kato BS, et al. The association between physical activity in leisure time and leukocyte telomere length. Arch Intern Med. 2008;168(2):154-158. doi:10.1001/archinternmed.2007.39

  3. Savela S, Saijonmaa O, Strandberg TE, et al. Physical activity in midlife and telomere length measured in old ageExp Gerontol. 2013;48(1):81-4. doi:10.1016/j.exger.2012.02.003

  4. Rizvi S, Raza ST, Mahdi F. Telomere length variations in aging and age-related diseases. Curr Aging Sci. 2014;7(3):161-7. doi:10.2174/1874609808666150122153151

By Mark Stibich, PhD
Mark Stibich, Ph.D., FIDSA, is a behavior change expert with experience helping individuals make lasting lifestyle improvements.