The human heart is a muscle about the size of a fist, and it beats more than 3 billion times during the average person's lifetime. It pumps the equivalent of more than 1 million barrels of blood through the body during an average lifetime, supplying the body’s internal systems with oxygen and other nutrients required for them to function. In one minute, a healthy heart beats about 80 times, which adds up to 115,200 beats per day and more than 42 million beats per year. It circulates about 6 quarts (5.6 liters) of blood through the entire body three times every minute.
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