The nine common causes of syncope include: 1. Cardiogenic syncope is related to a sharp decrease in heart beat output due to cardiac arrhythmia and myocardial infarction. 2. Cerebral syncope is caused by intracranial and extracranial cerebrovascular lesions, cerebral atherosclerosis, etc., resulting in strong cerebral vasoconstriction and cerebral hypoxia. 3. Postural syncope is related to a sudden change in position, sudden standing up or sitting up, resulting in a decrease in blood pressure. 4. The syncope is caused by autonomic dysregulation, which is mainly manifested by a large amount of urination or violent continuous coughing. 5. large amount of blood loss, hemorrhagic shock, resulting in a sharp drop in blood circulation. 6. large amount of water loss, dehydration, resulting in syncope. 7. fever, high body temperature, may cause syncope. 8. sudden increase in blood pressure can also lead to syncope. 9. Hypoglycemia or hyperventilation can also cause syncope symptoms.