The volume of blood pumped out per minute by the ventricles of the heart. It is one measure of the heart's efficiency. At rest, the heart of a healthy adult will pump between 2.5 and 4.5 litres of blood every minute. Exercise will raise this to as much as 30 litres a minute but, if this figure is low, it suggests that the heart muscle may be diseased or that the person has suffered severe blood loss.