By MyHealthNewsDaily Staff

Even a short bout of exercise can change your genes in ways that may ultimately make you stronger, a new study suggests.

The researchers studied genes in the muscles of men and women before and after they spent 20 minutes on an exercise machine.

After exercise, there were chemical changes in genes within the muscle cells, and these same genes were increased in expression. In other words, exercise helped "turn on" these genes, according to the study.

When the researchers made muscles contract in lab dishes, they saw similar changes to the DNA.

These changes appear to happen soon after exercise, which ultimately reprograms our cells for stronger muscles and greater endurance.

Our muscles adapt to what we do, said study researcher Juleen Zierath, of the Karolinska Institute in Sweden. "If you don't use it, you lose it, and this is one of the mechanisms that allows that to happen," Zierath said.

For those who don't like to work up a sweat, there may be hope. When the researchers exposed muscle cells from rats to caffeine, they saw changes in genes that were similar to those seen during exercise. In some ways, caffeine mimics the effect of exercise by causing an increasing in calcium levels inside cells, the researchers said.

However, the researchers don't recommend drinking coffee in place of exercise, Zierath said.

source:http://todayhealth.today.msnbc.msn.com/_news/2012/03/06/10594619-just-20-minutes-of-exercise-can-change-your-genes