The proper heart rate is regular, paced rhythm. The frequency of the heartbeat depends on the activity the individual is performing (resting or exercising) and is measured by the number of contractions of the heart over a unit of time, usually per minute. Therefore it is expressed in BPM (beats per minute). Heart rate can vary widely, but is usually between 60 bpm and 100 bpm in an individual at rest or usual activities.
For a resting adult individual, a heart rate of 100 bpm persistently may be considered high and this may indicate low level of aerobic fitness, which indicates that the individual should engage in physical exercise that provides good aerobic fitness and regulates the heart rate.
The medulla (the brain stem) contains the cardiac, respiratory, vomiting, and vasomotor centers and regulates autonomic, involuntary functions such as breathing, heart rate, and blood pressure.
