Athletes trained for endurance, such as swimmers and marathon runners, have a higher stroke volume at rest mainly because they have
When athletes are trained intensively, or for that matter if any person exerts himself in tiring work, the oxygen and consequently the blood supply demand from the body increases. Therefore, the heart compensates by pumping more blood per min or beat to make up for the demand. Therefore, when that person is at rest, because his heart is able to pump more blood per beat, what blood would have been pumped by 70 beats, now gets pumped by only 60 beats. This is referred to as resting bradycardia. Healthy young adults and athletes often have heart rates of less than 60 beats a minute.