Why could exercise affect your DNA?

We know that exercise can change how our bodies look, but a new study highlights that the effects run far deeper than that: acute exercise can alter DNA.

The effects are seen not in the genetic code or sequence itself, but in a natural process in the body called DNA methylation, which places chemical entities called methyl groups onto DNA to control how genes are turned on and off.

If you think of the DNA molecule as a train track where genes get turned on when the train runs along it, then methyl groups attached to DNA are like rocks on the track that block the train: they stop that particular gene being turned on.

The new study, just published in Cell Metabolism, took biopsies of skeletal muscle from human volunteers before and three hours after exercise. And what the researchers found was that acute exercise leads to transient changes in DNA methylation.

The findings reinforce the importance of exercise as a means of maintaining or increasing the expression of metabolic genes that help control the health of cells, according to Dr Donal O’Gorman, director of the Centre for Preventive Medicine at Dublin City University, who was involved in the study.

“The changes in methylation and [gene] expression for the genes studied are important for mitochondrial function, glucose transport as well as fat transport and oxidation,” he says.

“The findings support the view that regular activity is necessary for metabolic health and the prevention of chronic diseases such as type 2 diabetes.”