The causes of headaches caused by long sleep are mainly seen in three aspects: First, the human body is excited by the vagus nerve during sleep, the heart rate slows down, blood pressure drops, and blood flow slows down, making the blood supply to the brain decrease. Long sleep, the brain will be in a state of low blood supply for a long time, which may cause local hypoxia, which will make people feel dizzy or even headache, it is best to keep the sleep time at 8 hours. Second, the time of light sleep is too long. Under normal circumstances, deep sleep and light sleep is in alternation, the human body sleeps for a long time, just deep sleep is not increased, the increase is the time of light sleep. When in the state of light sleep, cerebral blood flow will increase, making the blood vessels dilate, and the nerves distributed in the blood vessels will be stretched and cause irritation, forming the symptoms of headache. Third, long sleep will make breathing slower and carbon dioxide accumulates in the blood. If the sleep time reaches more than ten hours, the carbon dioxide accumulated in the blood will turn into anesthetics for the body, which will cause people to be drowsy and feel dizzy or even have headache symptoms.