Re: How many heart beats does it take for blood to complete one cycle?

Your body has about 5.6 litres of blood. This 5.6 litres of blood circulates through the body three times every minute. In one day, the blood travels a total of 19,000 km (12,000 miles). This is an average estimation and will vary from one person to another and within a person’s body.

There are two main circulatory systems in which blood is involved:

Pulmonary Circulation is the portion of the cardiovascular system which carries oxygen-depleted blood away from the heart, to the lungs, and returns oxygenated blood back to the heart.

Systemic circulation is the portion of the cardiovascular system which carries oxygenated blood away from the heart, to the body, and returns oxygen-depleted blood back to the heart.

Some blood will travel from the heart to the heart itself, this will happen within one heartbeat. Other blood portions will travel to the limbs, organs and brain taking a different amount of time to return to the heart. Blood cells live about 120 days which means that they will probably reach every part of your body in their lifetime (this would be equivalent to about 200,000 heartbeats).

References: http://www.pbs.org/wgbh/nova/eheart/facts.html
http://www.americanheart.org/presenter.jhtml?identifier=10000056
http://www.acc.org/media/patient/index.htm
http://www.tchin.org/