We all know the health benefits of exercise programs. But how do they work?

New research may finally clarify the mysterious cellular process whereby the body derives health benefits from regular exercise. The New York Times reports that a recent series of studies shed some valuable light on the age-old conundrum by showing that exercise appears to alter the way our genes operate.

While every cell of your body contains your entire genetic blueprint, only a fraction of this genome is active at any given time. Genes coding for various things are constantly turned on and off, sometimes at a very rapid rate, expressing proteins that influence a variety of physiological functions. These activity patterns are determined by several different processes; however, one of the most powerful — and most fascinating — is called methylation.

How Exercise Programs Affect Methylation

Methylation refers to the process whereby clusters of carbon and hydrogen atoms (known as "methyl groups") attach to the exterior of a gene in order to influence the rate at which that gene communicates with the rest of the body — sometimes by accelerating expression, sometimes by imposing a speed limit.

The reason this process is so fascinating is that it appears to be determined largely by certain conscious decision and routines. Methylation, in other words, is influenced by the way you actually live your life.

In a study published in the journal PloS One, a Swedish team of researchers found that the benefits of exercise may stem from its ability to affect this process in profound and diverse ways. By comparing fat cells collected from a group of men before and after a six-month workout program, the researchers found that exercise altered the methylation pattern in numerous genetic locations — particularly in genes whose patterns had previously been linked to fat storage and a heightened risk of developing obesity or diabetes.

One Workout Can Trigger Health Benefits

"Our data suggest that exercise may affect the risk for Type 2 diabetes and obesity by changing DNA methylation of those genes," senior author Charlotte Ling, an associate professor at Lund University, told The New York Times, explaining that the new findings "are additional proof of the robust effect exercise can have on the human body, even at the level of our DNA."

Exercise, it seems, can convert risky gene expression into healthy gene expression. What's more, the researchers noted that the influence of exercise on methylation is more or less immediate, kicking in after a single workout.

How's that for motivation?

Source: Rönn T, Volkov P, Davegårdh C, Dayeh T, Hall E, et al. (2013) "A Six Months Exercise Intervention Influences the Genome-wide DNA Methylation Pattern in Human Adipose Tissue." PLoS Genet 9(6): e1003572. doi:10.1371/journal.pgen.1003572