Experts say exercise actually alters your DNA. A study found that healthy but inactive young adults experienced an immediate change to their muscle cells' genetic material when they engaged in a 20-minute workout on a stationary bicycle.
The changes were seen specifically in areas that affect genes responsible for energy metabolism. The underlying genetic code stayed the same, but the exercise made the muscles more efficient.
The study was conducted on 14 young men and women. It was published in the journal Cell Metabolism.
CNN contributed to this report.