We know that exercise can make us fitter and reduce our risk for illnesses such as diabetes and heart disease. But just how a run or a bike ride might translate into a healthier life has remained baffling. Now new research reports that the answer may lie, in part, in our DNA. According to a new study , exercise changes the shape and functioning of our genes, an important stop on the way to improved health and fitness.
The human genome is astonishingly complex and dynamic, with genes constantly turning on or off, depending on what biochemical signals they receive from the body .When genes are turned on, they express proteins that prompt physiological responses elsewhere in the body . Scientists know that certain genes become active or quieter as a result of exercise. But they hadn’t understood how those genes know how to respond to exercise.
Enter epigenetics, a process by which the operation of genes is changed, but not the DNA itself. Epigenetic changes occur on the outside of the gene, mainly through a process called meth ylation. In methylation, clusters of atoms, called methyl groups, attach to the outside of a gene like microscopic mollusks and make the gene more or less able to receive and respond to biochemical signals from the body . Scien the body . Scientists know that m e t hy l at i o n patterns change in response to life in response to life style. Eating certain diets a or being exposed to pollutants, t for instance, can change methyla tion patterns on some genes and affect what proteins they express.y Far less has been known about exercise and methylation. So for a study published this month in Epigenetics, scientists at the Karolinska Institute in Stockholm recruited 23 young volunteers for a series of physical and medical physical and medical tests, including a muscle biopsy , and then asked them to exercise half of their lower bodies for three months. The volunteers were asked to cycle with only one leg, leaving the other unexercised. In effect, each person became his or her own control group. Both legs would undergo methylation patterns influenced by one’s entire life, but only the pedalling leg would show changes linked to exercise.The volunteers pedalled one-legged for 45 minutes, four times per week. Then the scientists repeated the muscle biopsies and other tests. The exercised leg was more powerful now than the other, showing that the exercise had resulted in physical improvements.The changes within the muscle cells’ DNA were more intriguing.Using sophisticated genomic analysis, the researchers determined that more than 5,000 sites on the genome of muscle cells from the exercised leg now featured new methylation patterns. Some showed more methyl groups; some fewer. But the changes were significant and not found in the unexercised leg.
The scientists now better understand one more step in the complicated processes that make exercise so good for us. The message of this study is unambiguous. As Malene Lindholm, who led the study , pointed out: “Through endurance training -a lifestyle change that is easily available for most people and doesn’t cost much money , we can induce changes that affect how we use our genes and, through that, get healthier and more functional muscles that ultimately improve our quality of life.”
