How exercise changes fat and muscle cells
EXERCISE improves health, reducing most people's risks of developing diabetes and growing obese.
But just how, at a cellular level, exercise performs this beneficial magic remains mysterious to a surprising degree.
Several striking new studies, however, offer some clarity by showing that exercise seems able to drastically alter how genes operate.
One powerful means of affecting gene activity involves a process called methylation, in which methyl groups - a cluster of carbon and hydrogen atoms - attach to the outside of a gene and make it easier or harder for that gene to receive and respond to messages from the body.
Researchers affiliated with the Lund University Diabetes Centre in Sweden conducted a study, recruiting several dozen sedentary but generally healthy adult Swedish men and sucking out some of their fat cells.
The researchers mapped the existing methylation patterns on the DNA within those cells and measured the men's body composition, aerobic capacity, waist circumference, blood pressure, cholesterol levels and similar markers of health and fitness.
Then 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.
They had also altered the methylation pattern of many of the genes in their fat cells.
The genes showing the greatest change in methylation also tended to be those that had been identified previously as playing some role in fat storage and the risk of developing diabetes or obesity.
Meanwhile, other studies have found that exercise has an equally profound effect on DNA methylation within human muscle cells, even after a single workout.
Associate Professor Charlotte Ling of Lund University said the new findings "are additional proof of the robust effect exercise can have on the human body".