Cardiac output or heart output is the amount of blood pumped by heart (or more precisely by one ventricle either right or left) per minute. Cardiac output can be calculated as:
Heart rate $\times$ Stroke volume (i.e.,the volume of blood ejected by one ventricle during each beat). Heart of a normal person beats 72 times per minute and pumps out about 70 ml of blood per beat and about 5 litres per minute which· is equivalent to the total· body blood volume (about 5.5 litres).