What are the fitness benefits of aerobic exercise?
How our bodies adapt Here’s what happens inside your body when you do aerobic exercise regularly: 1. Your heart gets stronger and pumps more blood with each beat (larger stroke volume). Elite athletes, as I just mentioned, can have stroke volumes more than twice as high as average individuals. But it’s not just that. Conditioned hearts also have greater diameter and mass (the heart’s a muscle too and gets bigger when you train it), and they pump efficiently enough to allow for greater filling time, which is a good thing because it means that more blood fills the chambers of the heart before they pump so that more blood gets pumped with each beat. 2. Greater stroke volume means the heart doesn’t have to pump as fast to meet the demands of exercise. Fewer beats and more stroke volume mean greater efficiency. Think about a pump emptying water out of a flooded basement. The pump works better and lasts longer if it can pump larger volumes of water with each cycle than if it has to pump fast
