The main causes of excessive drowsiness are: 1, brain cell hypoxia resulting in excessive drowsiness, due to brain cell hypoxia, arterial blood oxygen saturation is insufficient, carbon dioxide partial pressure is too high, oxygen partial pressure is too low and lead to ventilation blood flow ratio malfunction, will cause brain ischemia and hypoxia response, common pulmonary insufficiency, chronic pulmonary heart disease, pulmonary hypertension and other conditions. 2, dyslipidemia, usually due to hyperlipidemia and blood viscosity and trigger excessive drowsiness. 3, there are also causes of insufficient blood supply to the cerebral arteries and coronary arteries of the cardiovascular system, which often lead to chest tightness, shortness of breath, drowsiness, fatigue, and tiredness. It is recommended to seek professional consultation with a doctor at the hospital for appropriate symptomatic treatment.