How a Healthy Heart Works
The average human heart beats 100,000 times each day and 36 million times annually. While only the size of a clenched fist, your heart pumps about 2,000 gallons of blood each day and nearly 700,000 gallons each year.
Your heart circulates blood throughout your body. Each time you take a breath, your lungs are filled with fresh oxygen. Your lungs are responsible for delivering oxygen to the blood. Then your heart pumps that oxygenated blood to different parts of your body.
The right side of your heart -- right atrium and right ventricle -- pumps blood to your lungs, where blood cells get that fresh oxygen. This oxygenated blood is then returned to the left side of your heart -- left atrium and left ventricle -- where the oxygenated blood is pumped out to the rest of the body, supplying oxygen and nutrients that your organs need to function normally. The cells in your body remove the oxygen from the blood. The oxygen-depleted blood is returned to the right atrium, where it all started. This wonderful round trip is known as the circulation of blood.