A recent paper published on PLoS One explains the molecular basis of how exercise changes the human body’s muscles and fat cells. Turns out, it’s the methylation (addition of CH3-groups) to various DNA segments that has the capacity to turn on/off certain genes. The New York Times summarizes:
Of the new studies, perhaps the most tantalizing, conducted principally by researchers affiliated with the Lund University Diabetes Centre in Sweden and published last month in PLoS One, began by recruiting several dozen sedentary but generally healthy adult Swedish men and sucking out some of their fat cells. Using recently developed molecular techniques, the researchers mapped the existing methylation patterns on the DNA within those cells. They also measured the men’s body composition, aerobic capacity, waist circumference, blood pressure, cholesterol levels and similar markers of health and fitness.
Then they asked the men to start working out. Under the guidance of a trainer, the volunteers began attending hour-long spinning or aerobics classes approximately twice a week for six months. By the end of that time, the men had shed fat and inches around their waists, increased their endurance and improved their blood pressure and cholesterol profiles.
Less obviously, but perhaps even more consequentially, they also had altered the methylation pattern of many of the genes in their fat cells. In fact, more than 17,900 individual locations on 7,663 separate genes in the fat cells now displayed changed methylation patterns. In most cases, the genes had become more methylated, but some had fewer methyl groups attached. Both situations affect how those genes express proteins.
The genes showing the greatest change in methylation also tended to be those that had been previously identified as playing some role in fat storage and the risk for developing diabetes or obesity.
The overarching implication of the study’s findings, says Juleen Zierath, a professor of integrative physiology at the Karolinska Institute and senior author of the study, is that DNA methylation changes are probably “one of the earliest adaptations to exercise” and drive the bodily changes that follow.