The normal adult nighttime heart rate is 50 to 70 beats per minute, and a nighttime heart rate of 37 beats per minute is lower than the normal nighttime heart rate and usually indicates the presence of bradycardia. In general, the adult daytime heart rate is 60-100 beats per minute. Because of the parasympathetic excitation at night, the heart rate will be physiologically slowed down, so the heart rate at night after people fall asleep is usually 50 to 70 beats per minute. If the heart rate is lower than 50 beats per minute at night, this may indicate the presence of bradyarrhythmia. Bradyarrhythmia is usually caused by sinus bradycardia, atrioventricular block, etc. This symptom may affect the pumping function of the heart, resulting in insufficient blood in the peripheral circulation, which may cause a series of adverse effects on the human body, such as dizziness, etc. If bradycardia is present, the heart rate is usually 50 to 70 beats per minute at night. If there is bradycardia, it is recommended to go to the hospital in time to improve the relevant examination, under the guidance of the doctor for treatment.