the cells that control the resting heart rate are found in atria.
where are the cells that control the resting heart rate found?
atria
section::::in different circumstances.





























heart rate is not a stable value and it increases or decreases in response to the body's need in a way to maintain an equilibrium (basal metabolic rate) between requirement and delivery of oxygen and nutrients. the normal sa node firing rate is affected by autonomic nervous system activity: sympathetic stimulation increases and parasympathetic stimulation decreases the firing rate. a number of different metrics are used to describe heart rate.





























section::::in different circumstances.:resting heart rate.





























normal pulse rates at rest, in beats per minute (bpm):
heart rate
the basal or resting heart rate (hr) is defined as the heart rate when a person is awake, in a neutrally temperate environment, and has not been subject to any recent exertion or stimulation, such as stress or surprise. a large body of evidence indicates that the normal range is 60-100 beats per minute. this resting heart rate is often correlated with mortality. for example, all-cause mortality is increased by 1.22 (hazard ratio) when heart rate exceeds 90 beats per minute. the mortality rate of patients with myocardial infarction increased from 15% to 41% if their admission heart rate was greater than 90 beats per minute. ecg of 46,129 individuals with low risk for cardiovascular disease revealed that 96% had resting heart rates ranging from 48-98 beats per minute. finally, expert consensus reveals that 98% of cardiologists believe that the "60 to 100" range is too high, with a vast majority of them agreeing that 50 to 90 beats per minute is more appropriate. the normal resting heart rate is based on the at-rest firing rate of the heart's sinoatrial node, where the faster pacemaker cells driving the self-generated rhythmic firing and responsible for the heart's autorhythmicity are located. for endurance athletes at the elite level, it is not unusual to have a resting heart rate between 33 and 50 bpm.
heart rate