Sleeping and dreaming, the reasons are as follows: 1, with excessive brain work, after sleeping brain cells continue to work, perform certain calculations, etc.; 2, playing computer games, watching some comedy films, doing strenuous exercise or excessive excitement before going to bed, resulting in more hyperactive brain nerve cells; 3, may also be related to excessive tension, anxiety, stress, neurasthenia, etc., which affects the quality of sleep, resulting in Shallow sleep time is prolonged; 4, often sleep on your stomach or sleep, the habit of placing your hand on the heart, will also appear more dreams or nightmares symptoms; 5, insufficient blood supply to the heart muscle, heart failure, resulting in breathing difficulties; 6, insufficient blood supply to the brain, lack of oxygen to the brain; 7, too much food or excessive hunger before going to bed, may affect the quality of sleep, resulting in the phenomenon of dreaming when you fall asleep.