The heart rate of normal people during sleep is mostly above 45 beats/min. The heart rate of normal adults in a waking, quiet state is sinus rhythm, with a range of 60-100 beats/min. Most normal adults have a heart rate of about 75 beats/min. However, this is not an absolute value, most patients only have a heart rate above 45 beats/min during sleep, which is normal, but some patients who usually have severe bradycardia may have a heart rate of about 40 beats/min during sleep, and most patients do not need to worry too much as long as they do not have symptoms. If there are arrhythmias, such as atrioventricular block of second degree or higher, or chronic atrial fibrillation, most patients may have a long gap and have a heart rate of 35 beats/min or less.