The causes of drowsiness can be divided into the following aspects: 1, caused by the spirit of bad, too fatigue, such as the night sleep is not good, the daytime will certainly appear drowsiness. 2, caused by physical diseases, such as wind and cold cold or other diseases, the spirit will not be very good, but also prone to cause drowsiness. Some depressed patients are more nervous and always in a state of anxiety, which can also lead to daytime sleepiness. Some young and middle-aged people may be in a state of mental insanity at times because they are too obese, which is related to their health. Some elderly patients have cerebrovascular diseases, which leads to a state of hypoxia and ischemia in the skull. In this case, the oxygen supply to the whole head is insufficient, and the symptoms of drowsiness can also appear. It also includes the symptoms of drowsiness caused by specialized narcolepsy, which is very serious. Sometimes, they fall asleep while walking during the day. If this happens, you should go to the hospital immediately.