Since the heart is on the left side of the chest, it is a normal physiological phenomenon for patients to sleep on the left side and feel their heart beating significantly. In addition to normal physiological phenomenon, it may also be caused by sinus tachycardia and other diseases, which can be treated with surgery or medication according to the cause. 1. Physiological phenomenon: Because the environment is quiet at night, the individual’s attention is more concentrated, so the sound of the heartbeat felt at night will be more obvious. If there is no other physical discomfort, it is a normal physiological phenomenon and does not require treatment. 2. Sinus tachycardia: Sinus tachycardia is an arrhythmia caused by the sinus node giving out impulses at a faster frequency. It is recommended to consult the doctor in time and use medication under the doctor’s guidance, such as metoprolol, bisoprolol, verapamil, etc., and use catheter ablation and other surgical treatments if necessary. Therefore, patients with symptoms of significant heart beating on the left side of the sleep, excluding physiological factors, it is recommended to consult a doctor in time to identify the cause of the disease and timely treatment. Before taking medication for treatment, patients are advised to consult their doctors to avoid other damages to the body caused by taking medication improperly.