the group of cells that control the natural resting heart rate are found at sinoatrial node.
the group of cells that control the natural resting heart rate are found at sinoatrial node.
where are the group of cells that control the natural resting heart rate found?
sinoatrial node
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
other studies have shown that a high resting heart rate is associated with an increase in cardiovascular and all-cause mortality in the general population and in patients with chronic disease. a faster resting heart rate is associated with shorter life expectancy and is considered a strong risk factor for heart disease and heart failure, independent of level of physical fitness. specifically, a resting heart rate above 65 beats per minute has been shown to have a strong independent effect on premature mortality; every 10 beats per minute increase in resting heart rate has been shown to be associated with a 10–20% increase in risk of death. in one study, men with no evidence of heart disease and a resting heart rate of more than 90 beats per minute had a five times higher risk of sudden cardiac death. similarly, another study found that men with resting heart rates of over 90 beats per minute had an almost two-fold increase in risk for cardiovascular disease mortality; in women it was associated with a three-fold increase.
heart rate