Heart rate

Heart rate is a term used to describe the frequency of the cardiac cycle. Ususally it is calcuated as the number of contractions (beats) of the heart in one minute. As such heart rate is usually expressed as "beats per minute" (bpm). When resting, the adult human heart beats at about 70 bpm (males) and 75 bpm (females), but this rate varies between people. However, the reference range is taken between 60 bpm (if less termed bradycardia) and 100 bpm (if greater, termed tachycardia).

Related Topics:
Heart - Minute - Human - Bradycardia - Tachycardia

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The body can increase the heart rate in response to a wide variety of conditions in order to increase the cardiac output (the amount of blood ejected by the heart per unit time). Exercise causes a normal person's heart rate to increase above the resting heart rate. As the physical activity becomes more vigorous, the heart rate increases more. With very vigorous exercise, a maximum heart rate can be reached.

Related Topics:
Cardiac output - Exercise

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The pulse is the most straightforward way of measuring the heart rate, but it can be deceptive when some strokes do not lead to much cardiac output. In these cases (as happens in some arrhythmias), the heart rate can be (much) higher than the pulse.

Related Topics:
Pulse - Arrhythmia

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