2.00 Hz 1.20 Hz Berkow, Robert. The Merck Manual of Medical Information . The normal heart rate at rest is usually between 60 and 100 beats per minute. When the heart muscle, called cardiac muscle, contracts it pushes blood through the chambers and into the vessels. The heartbeat is a vital, involuntary action for a living human being and the heart continues to pump throughout an individuals life stopping only at death.
Heartbeats vary depending on various factors such as age, physical state, and stimuli.
A child has a smaller heart and therefore their heart needs to beat faster in order to pump the proper amount of blood. The heartbeat rate for infants is 120 per minute, for a child is about 90 times per minute, and for a person over age 18 is about 70 times per minute. A physically fit person has a lower heart rate as compared to an inactive person. Stimuli resulting in stress, fear or excitement will result in a rapid heartbeat. Nerves connected to the heart regulate the speed with which the cardiac muscle contracts.