There are many causes of low heart rate, such as athletes, sleep status, diseases, medications, etc. The cause needs to be clarified and treated if necessary. Low heart rate is clinically referred to as sinus bradycardia, that is, the patient’s heart rate is lower than the lower limit of the normal level, generally refers to the heart rate is less than 60 beats per minute, which is a type of arrhythmia. There are many reasons for the appearance of this arrhythmia, such as athletes due to long-term training, strong heart function, heart ejection volume, the heart rate can be lower than the general population. In addition, the body consumes less energy and the metabolic rate decreases during sleep, which can also lead to bradycardia. All of these conditions are normal physiological phenomena and generally do not require treatment. Pathological factors such as hypothyroidism, the body’s thyroid hormone levels can lead to sinus bradycardia, this situation should be timely use of medication, such as levothyroxine; digitalis drugs, β-blockers and other drugs used improperly can also lead to sinus bradycardia, the drug should be discontinued in time for symptomatic treatment. Because of the existence of indications and contraindications for drug therapy, improper application can lead to adverse consequences, so patients with sinus bradycardia should be treated with drugs under the guidance of a professional physician.