A low resting heart rate is most closely associated with which type of individual?

A low resting heart rate is most closely associated with outstanding athletes because of their adaptations to regular, intense physical training. Athletes often have a higher cardiac efficiency, which allows their hearts to pump a greater volume of blood per beat. This means that they require fewer beats per minute to maintain adequate blood flow and oxygen delivery at rest.

As individuals consistently engage in aerobic activities, such as running, swimming, or cycling, their cardiovascular systems become more efficient. This efficiency can be attributed to several factors, including an increase in stroke volume (the amount of blood pumped by the heart with each beat) and improved vagal tone—which is related to the influence of the parasympathetic nervous system—and offers better regulation of heart rate.

Conversely, sedentary individuals typically exhibit higher resting heart rates because their cardiovascular systems are not conditioned to operate as efficiently. Likewise, moderately active individuals may have lower resting heart rates than sedentary people, but they generally do not achieve the lower rates seen in well-trained athletes. Lastly, individuals with high stress levels may experience elevated resting heart rates due to increased sympathetic nervous system activity, which can lead to a more rapid heart rate even at rest.