Sudden death does not occur in most cases of sinus bradycardia. Sinus bradycardia, medically known as sinus bradycardia, is a sinus rhythm of 50-60 beats per minute with no other symptoms and is mostly normal physiologically and does not require treatment. Sinus bradycardia is a common clinical phenomenon, not a disease, and occurs in healthy adults during sleep, in athletes and in the elderly. However, if sinus bradycardia persists below 40 beats per minute and the heart rate does not increase during activity, it is called pathological sinus node syndrome. This condition is more dangerous and the patient needs to undergo 24-hour ambulatory ECG monitoring. If the patient’s heart rate is less than 50 beats/min in the quiet state and symptoms such as dizziness, transient blackout, transient loss of consciousness, chest tightness, and weakness occur, it is recommended that the patient be seen immediately at a hospital cardiology department. In summary, if sinus bradycardia is greater than 50 beats/min and no other symptoms are combined, patients need not be overly nervous and will not die suddenly, and in most cases the heart rate will increase accordingly after activity.