The common causes are as follows: 1. If you are an elderly person, it is recommended to check the vascular ultrasound of the brain to see if the blood is caused by high lipid and high viscosity, which leads to a slowing of blood flow. If this is the cause, it is recommended to improve the circulation, and if necessary, oral lipid-lowering drugs. 2, recently the sleep is particularly high, if the young people are considered to be due to fatigue or eating fatty food, it is recommended that the patient pay attention to rest, while low salt, low-fat diet. 3, recently the sleep is particularly high consider and the weather also has a certain relationship, Chinese medicine speaks of spring, autumn harvest, winter collection, generally in autumn due to the longer night time. The night time is longer. So lead to the phenomenon of more sleep, if necessary, it is recommended that patients go to bed early and get up early to strengthen exercise.