Fainting, also known as syncope, is commonly referred to as fainting. Syncope is a short-lived loss of consciousness caused by transient cerebral ischemia and hypoxia. Syncope is a sudden, transient, transient loss of consciousness and fainting, caused by transient, widespread cerebral ischemia, hypoxia, and recover naturally in a short period of time. Etiology 1, cardiogenic syncope: due to cardiac arrhythmia, myocardial infarction and other reasons caused by a sudden decrease in the volume of heart beats. Especially common in atrioventricular block, ventricular paroxysmal tachycardia, etc. 2. Reflex syncope: This is a common type of syncope. (1) Due to increased vagal tone. (2) Postural syncope, which occurs mostly when the prone position is changed to upright. (3) Carotid sinus allergic syncope. (3) Urinary syncope: occurs suddenly during or after urination, mostly in men, especially when they get up at night to urinate or when they urinate too long. 4, cerebral syncope: fainting caused by intracranial and extracranial cerebrovascular lesions or damage to the vasomotor center itself. 5, other syncope: common in people with chronic obstructive pulmonary disease or with emphysema. Blood and water loss syncope can be caused by acute massive blood and water loss from various causes, resulting in a rapid decrease in the effective circulating volume, alpine adaptation and hypoglycemic syncope, due to insufficient oxygen and blood sugar content in the inhaled air.