With each beat, the heart pumps about 2.5 ounces (70 ml) of blood into the body via the aorta. That’s about five quarts (or about five liters) per minute, nearly all the blood in your body. And that’s just at rest! During exercise, you heart’s output can easily triple. Amazingly, all this work is done for the low, low cost of about 2 calories per beat.
