Vicki Horne, age 11, of Rowayton, Connecticut, for her question:

How fast does the heart beat?

A doctor counts a patient's pulse to check the normal or average heartbeat. Usually he is not alarmed if the rate is between 50 and 85 times a minute. The average heartbeat for a healthy man is about 72 times per minute. The average woman's is somewhat faster, perhaps 76 to 80 times per minute. Young children have faster heartbeats and most seven¬ year olds are around 90 times a minute. In older folks, the normal pulse slows down to 65 or even 50 times per minute.

At all ages, the human heart can beat at different speeds, slower or faster to meet the needs of the body. Its business is to pump blood around the body, carrying oxygen fuel to the busy cells. During strenuous exercise, muscles use up more oxygen and the heart beats faster to keep the supplies coming. When the body sleeps, the cells slow down    and so does the heartbeat