How is heart rate typically defined?

Heart rate is defined as the frequency of the cardiac cycle measured in beats per minute. This parameter reflects how many times the heart contracts and pumps blood in a minute, which is a crucial aspect of cardiovascular function.

The measurement of heart rate is important in various contexts, such as assessing physical fitness, understanding cardiovascular health, and monitoring responses to exercise or exertion. A typical resting heart rate for adults ranges from 60 to 100 beats per minute, with athletes often having lower resting rates due to more efficient heart function.

In the context of the other options, the number of breaths taken per minute pertains to respiratory rate, not heart rate. The volume of blood pumped by the heart in one minute refers to cardiac output, which is a distinct measurement that combines heart rate and stroke volume. Blood pressure indicates the force exerted on the walls of blood vessels but does not reflect the heart's activity in terms of beats. Thus, option B accurately captures the essence of heart rate distinctively from these other cardiovascular metrics.