How Exercise Can Change Your DNA

Exercise does a lot of good things — it burns calories, helps keep your weight in check and lowers your risk of heart disease, stroke and diabetes. Now add one more thing to the list: physical activity can change your DNA.

Unlike the aberrations and genetic mutations caused by carcinogens and toxins, exercise-induced alterations to DNA are more like tune-ups, helping muscles to work better and more efficiently. What’s more, these changes occur even after a single 20-minute workout.

Juleen Zierath, a professor of physiology at the Karolinska Institute in Stockholm, reports with her colleagues in the journal Cell Metabolism about these very early changes that muscle cells undergo the first time you get off the couch and into the gym. The researchers worked with a group of 14 young men and women who were relatively sedentary, and asked them to work out on an exercise bike that measured their maximum activity levels. The participants also volunteered to give up a little bit of muscle, from their quadriceps, in a relatively painless biopsy procedure performed under local anesthesia. The researchers took the biopsy of muscle cells once before the participants exercised, and again within 20 minutes afterward.

Using the biopsied samples, researchers compared the activity in a series of muscle-related genes before and after exercise. More genes were turned on in the cells taken after the exercise and the participants’ DNA showed less methylation, a molecular process in which chemicals called methyl groups settle on the DNA and limit the cell’s ability to access, or switch on, certain genes. By controlling how much methylation goes on in certain cells at specific times, the body regulates which genes in the DNA are activated — that’s what differentiates the development of an an eye cell, for example, from that of a liver cell.