At present, most people usually go to bed late. Because of work or other reasons. Make it a good night’s sleep is not enough. Affect the body in many respects as follows 1. In a bad mood, who sleep only 4-5 hours per night. Tend to be a mood disturbances easy feel stress, anger can not control their own emotions. 2. The learning system reduced relaxation is not enough, can result in brain is perception. Processing thoughts down. 3. pain to the head. Leisure is not enough, it causes the blood to the brain is not enough, Thus the cause of headaches. 4. Alzheimer's disease. Insufficient sleep in Alzheimer disease. When old age will increase the risk of Alzheimer disease. Therefore, we should go to bed early. For the body to get enough rest.