The body is always sleepy, want to sleep is usually because of the following three reasons: First, the most common reason is the lack of oxygen in the brain, the lack of oxygen in the brain is usually because of the reduction of oxygen saturation, arterial blood oxygen partial pressure drop, carbon dioxide partial pressure increase, or because of the ventilation/blood flow ratio is out of proportion, often because of chronic pulmonary heart disease, pulmonary insufficiency, pulmonary hypertension, and therefore insufficient oxygenation triggered by. Second, always sleepy, want to sleep because of myocardial blood supply is insufficient and lead to cerebral ischemia state, often due to coronary atherosclerotic heart disease, and lead to coronary artery perfusion pressure is insufficient, and cause cerebral arteries vertebral – basilar artery blood supply deficiency syndrome. Third, often sleepy, want to sleep because of blood lipids or blood viscosity is too high, usually to high triglyceride anemia and high cholesterol anemia.