Nightmares are a matter of fear and trepidation, no matter how good the psychological quality, in the presence of nightmares, his mental state, are more vulnerable. If frequent nightmares occur, it is not good for physical and mental health. Nightmares do not appear for no reason, each time it comes there is a specific reason, either psychological or physical. Such as excessive tension, excessive excitement, in an unfamiliar sleep environment; or watching a horror movie or listening to a horror novel before going to bed. These are the psychological factors that cause nightmares. Nightmares appear physical reasons, mainly related to the bedroom is small, hot, dirty air, too thick bedding, improper sleep posture, chest pressure, etc. There is also too much dinner, or too little, in a state of hunger, which can easily induce nightmares. Nightmares are also inextricably linked to sleeping posture. Improper sleeping posture, especially sleeping on your back, which can easily cause strain on the neck muscles, ligaments, joints and other parts of the body, and compression of the heart and lungs, affecting the whistle, resulting in increased burden on the heart and lung function, poor whistle, then it will directly affect the quality of sleep. And improper sleeping posture, it is easy to make the cervical spine overbending, the direct consequence of this is to reduce the blood supply to the brain, resulting in cerebral ischemia and hypoxia and induced nightmares, and after waking up, the body will also appear dizzy, blurry eyes, weakness, and seriously affect the work of daily life. To avoid nightmares, the first thing is to have a good sleep environment, comfortable bed, fresh air; and do not eat, do not feel hungry, do not watch horror novels, movies and TV before going to bed; to wear soft and comfortable pajamas, try to sleep in the right position. If you can do these things, it is possible to reduce the nightmares.