Everybody knows that exercise is good for our bodies. New research suggests exercise could have effect that’s as far reaching as our DNA. Rather than just toning our bodies and reducing the risk for illness, exercise could actually be changing the shape and functioning of our genes. The human genome is very dynamic experiencing a continuous cycle of change, with genes constantly turning themselves on and off in response to biochemical signals from the body. Operation of the genes changed via an event called methylation. This is where methyl groups (clusters of atoms) attach to the exterior of the gene structure. As a result, the gene is rendered more or less able to receive and respond to the biochemical signals it received. One of the main catalysts for changing methylation patterns is lifestyle. This means that environmental factors, from certain food types to chemicals that we’re exposed to, can cause changes in methylation process, which can affect our health or our chances to develop certain diseases. The exact impact of exercise had not been fully explored until the scientists in Karolinska Institute in Stockholm decided to answer this question with a specially formulated study. They recruited 23 young men and women and asked them to undergo a series of physical performance and medical tests. Then they were asked to exercise their lower bodies for a period of three months. In order to rule out other environmental causes for altered methylation patterns, it was requested that they only exercise one leg so that the two limbs could be compared. After three months genomic analysis revealed more than 5,000 altered methylation patterns in the genomes of the exercised muscle cells. Most of these changes were identified as influencing energy metabolism, insulin response, and muscle inflammation. The study shows that through endurance training we can induce changes that affect our genes and, through that, improve our quality of life.