There are many reasons why heartbeat is 50 and weak, mainly divided into cardiac factors and non-cardiac factors, as follows: 1. Non-cardiac factors: such as intracranial disease, severe hypoxia, hypothermia, hypothyroidism, the use of amiodarone, beta-blockers, digitalis drugs, etc. This type of bradycardia can generally be treated or eliminated by the original cause of the disease can increase the heart rate. 2. Cardiac factors: The presence of slow arrhythmias such as sinus bradycardia and atrioventricular block should be considered. Some heart diseases can cause slow heart rate, such as myocarditis and heart failure, so the treatment is different according to the cause. If symptoms such as slow heart rate and fatigue occur, it is recommended to go to the hospital as soon as possible for relevant examinations to determine the cause of the disease so as to facilitate targeted treatment. It is recommended that patients should not judge or diagnose on their own based on a single result, but should consult a doctor in a timely manner, who will analyze the situation comprehensively and make a clear diagnosis according to the specific circumstances.