Women who maintain an active lifestyle as they get older may age more slowly than those who are more sedentary. Keeping up with your fitness routine could keep you younger! The science behind the discovery lies in our DNA. Throughout the course of our lives, our cells constantly replicate themselves. After each copy, tiny caps — called telomeres — at the end of our DNA strands shorten, exposing our chromosomes to decay. Shorter telomeres have been linked to heart disease, diabetes and cancer.