Do athletes have a big or a small heart? in terms of volumes of blood in there ventricles or diameter of the heart?

Bigger: In general, well trained athletes have a larger heart than sedentary people, which is capable of pumping more blood to keep up with activity needs. Hope this helps!

Atheletic Heart Synd: As the attached article indicates, most endurance athletes have bigger hearts and ventricular enlargement, due to extra work to pump larger volumes of blood for increased demand, with lower heart rates.indicating stronger individual strokes needed to accomplish the task