Want to look younger? Who doesn't? But what if you could actually be younger, at least in comparison to your peers. A new study suggests that people who are regularly physically active may not only ward off age-related diseases but might actually be biologically younger than those who don't exercise at all.

Researchers measured leukocyte telomeres, which (long story short) may shorten as people age. Those who exercised regularly had longer telomeres than those who didn't. In some cases, telomere length in active people was the same as that in those who were 10 years younger.

It's not cut-and-dried research, but it's a pretty firm indicator that exercise is an important part of a long and healthy life.