The Science of Fitness: Does Exercise Change Your DNA?

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There’s little doubt that focusing on fitness will make a big impact on your heart health, waistline, diabetes risk, stroke risk, cancer risk … the list could go on and on. The exact reason as to why exercise is so good for us has long confused even the experts. But recent research suggests that the answer may lie in a process called epigenetics.

Epi-what? Exercise, Epigenetics and You
Epigenetics is a fancy word that describes the study of the factors that influence how our genes work. These factors cause changes that happen on the outside of your genes, a process called methylation. Methylation changes the ability of a gene to receive and react to biochemical messages from the body.

Picture your genes almost like a string of lights: constantly turning on and off depending on which biochemical signals they’re receiving from the body.

Scientists know that methylation patterns are affected by lifestyle, diet and exposure to pollutants. They also know that even a single workout can change the methylation pattern on some of the genes in our muscle cells. The long-term effect exercise has on methylation patterns, however, has been a mystery until recently.

Genetics 101: The Exercise Experiment
Researchers in Stockholm, Sweden conducted a three month-long test involving 23 adult men and women. They had them exercise on a bicycle but only using one of their legs. The other leg served as a control.

As a reminder from eighth grade science class, the control in an experiment is the thing that stays the same. The variable is the thing (or things) that changes based on whatever the scientist is testing. Usually, the control and the variable come from two separate things. But in this instance, the control and variable were both on the same person (unexercised leg = the control, exercised leg = the variable).

This allowed scientists to test the effects of activity versus inactivity all within the same person! That means all other factors (lifestyle, diet, exposure to pollutants, etc.) remained the same, so that they could be certain the results showed only the effects of the exercise. Pretty neat, right?

The study participants had to bicycle at a moderate pace for 45 minutes, four times a week during the study. Muscle biopsies were performed before and after the training.

At the end of the study, as expected, the exercised leg was stronger, showing physical improvements to the muscle. But microscopic studies found that over 5,000 places on the muscle tissue of the exercised legs showed signs of new methylation patterns, while the unexercised leg tissue did not. Most of the genes that changed were connected to metabolism, insulin response and muscle inflammation.

The Final Proof
So what does that mean for us? Exercise affects how fit and healthy we become at the cellular level.

And since less than half of American adults (48 percent) don’t get the recommended amount of physical activity each week – 150 minutes of moderate exercise or 75 minutes of vigorous exercise – they’re doing themselves a big disservice. Those who consistently exercise are proven to:

  • Live longer
  • Have improved muscle and bone strength
  • Decrease their risk of stroke, heart disease, Type 2 diabetes, depression and many forms of cancer

And now we know why. We have the power (and scientific proof) to change how effectively our genes make us fitter and healthier through lifestyle changes and regular exercise. The entire picture isn’t filled in yet, but it’s another big, important piece of the biochemical puzzle.


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Categories: MoveWell