Sighing is usually a physiological phenomenon, sometimes it may also be manifested as chest tightness and shortness of breath, which can be seen in cardiovascular system diseases, respiratory system diseases and depression and other diseases. 1. Physiological reasons: usually, sighing is a kind of expression of helplessness and sadness, and occasional sighing will not cause serious effects on the body. 2. Pathological causes (1) Cardiovascular diseases: arrhythmia, viral myocarditis and other diseases can cause chest tightness and shortness of breath, which will be aggravated by activities, and even shock in serious cases. (2) Respiratory system diseases: bronchial asthma, chronic bronchitis, in addition to frequent sighing, shortness of breath, but also can be manifested in dyspnea, cough and other respiratory symptoms. (3) Depression: such patients often have sighs and sad faces, and also have symptoms such as anxiety and decreased concentration. If there is frequent sighing, and can be excluded from the physiological causes, it is recommended to go to the hospital in time.