Always sleepy, want to sleep, there are many factors: 1, environmental factors. The environment is relatively lack of oxygen, not ventilated. 2, psychological factors. Is in a bad mood, sad time, always thinking of something can not handle, the role of psychological suggestion will lead to special sleepy. 3, disease factors, such as colds, hypertension, or cervical spondylosis patients, may compress blood vessels caused by the lack of oxygen to the brain, caused by the performance of drowsiness. 4, external factors, such as some people like to eat some of the food and lead to sleepy, such as eating fat pills especially Easy to sleep. Because the drug contains elements that make appetite, stimulate the nerves in it, after eating, sleep, it is easy to gain weight. 5, the factor of fatigue. The body itself is very tired, need a bed, the biological clock will signal “very fatigue sleep it.