Maybe this will motivate you to work out. New research supports the idea that you don't need to spend hours at the gym everyday for your body to start feeling the positive effects of exercise. In fact, a single session on a stationary bike can affect your very DNA.

Okay, so your actual genetic code won't morph into that of Conan the Barbarian. But exercise sets signals in motion almost instantly that determine which genes get turned on and off. These what-are-called epigenetic changes signal to the muscles to, well, tone up. The study is in the journal Cell Metabolism. [Romain Barres et al., "Acute Exercise Remodels Promoter Methylation in Human Skeletal Muscle"]

Researchers recruited 14 men and women in their mid-20s who didn't usually exercise. After a short but intense spin on a bike, samples of their muscle tissue showed temporary, but big, changes in several types of epigenetic signals. Further tests showed that some of the same effects could be achieved with a jolt of caffeine.

Alas, black coffee can’t provide all the benefits of your morning workout. But if you get to the nearest coffee shop by running, you're definitely starting out on the right foot.

—Katherine Harmon

[The above text is a transcript of this podcast.]

