An average human heart pumps 1,900 gallons (7,200 litres) of blood around the body per day. The source of this information was www.montana.edu/craigs/How%20Your%20Heart%20Works.htm and was written by a doctor, and so is fairly reliable. The volume of blood pumped around the body in any period of time is calculable is you know the heart rate and the stroke volume. This value (stroke volume times heart rate) is called cardiac output, and is how much blood is pumped per unit time. The average human has roughly five litres of blood in their body, but the blood has to pass through the heart twice to make one full circuit of the circulatory system. (Once in to the right atrium from a major vein such as the vena cava, then through the pulmonary artery to the lungs via the right ventricle, then back into the left atrium via the pulmonary vein, and then out the aorta from the left ventricle. From there it goes through the body and comes back to the lungs from a major vein.) Consequently, blood will make on average 720 "laps" of your body a day, and blood plasma (the watery constituent of blood) will pass once fully around the body in just two minutes! Of course, these values are just averages and so are not representative of the total population, for example there will be differences in these statistics between men and women, or between adults and children. The above figures are statistics for an average healthy adult.
