According to one study, people who exercised at least four times a week saw increased mass in the important bottom left portion of the heart.

They also preserved elasticity, which reduces the risk of heart failure.

Texas researchers divided 121 healthy people with no evidence of heart disease into groups depending on whether they were inactive or lifelong exercisers.

The lifelong exercisers, all older than 65, were then divided into one of four exercise groups according to their frequency of exercise: non-exercisers, casual exercisers, committed exercisers, and master athletes.

Heart mass decreased in the inactive participants, but increased in the lifelong exercisers. The committed and master athletes (those who exercised four to seven days a week), had heart mass that was similar or exceeded that of their younger, inactive counterparts.