Many people have the habit of napping, napping can not only improve the efficiency of the daytime work, but also to eliminate sleepiness, maintain a good mood, but some people will appear after the nap dizziness, may be related to improper sleeping position, sleep duration, sleep immediately after meals, postural hypotension, etc. 1, nap position: most people nap on their stomachs, long-term napping on their stomachs will cause insufficient blood supply to the brain. After waking up, there may be dizziness, blurred vision, weakness and a series of symptoms of cerebral ischemia and hypoxia; 2, nap time: nap time is generally 30-60 minutes is appropriate, if the sleep time is too long or too short, will lead to dizziness and weakness after waking up; 3, sleep immediately after meals: after meals because the stomach is filled with food, a large amount of blood flow to the stomach, to reduce the blood supply to the brain, causing the brain blood supply Insufficient, after the nap will appear dizzy and weak symptoms; 4, postural hypotension: after the nap, if you get up too hard to cause a transient drop in blood pressure, dizziness, blackness and other discomfort, generally soon be able to relieve; 5, cold: if you have a cold, the cold itself will also appear dizzy and weak, no attention to warmth during the nap may aggravate the condition, wake up dizzy and weak. It is generally recommended to nap half an hour after meals, the ideal way to take a nap is to lie on your side in a quiet place away from light, if conditions do not allow the case can wear a U-shaped pillow on the neck, sleep against the back of the chair to reduce the squeezing stimulation of the body and so on.