Sympathetic nerves are part of the vegetative nerves that primarily regulate the activity of the heart and other internal organs. Under normal conditions, the sympathetic nerves, together with their opposite function, the parasympathetic nerves, regulate the balance of the body. When the body is in a state of tension, quarrel or anger, the sympathetic nerve activity plays a major role, sympathetic excitation will appear pupil dilation, heart rate increases, blood pressure increases, bronchial dilatation, gastrointestinal peristalsis slow, blood glucose, saliva secretion decreases and so on. Since the human body can not always be in a state of tension, so the parasympathetic nerves will play a role in relieving the body’s state of tension, in order to restore the normal situation. Usually have insomnia, irritability, irritability and other symptoms is the manifestation of neurasthenia, mainly related to plant nerve dysfunction, so usually must develop a good life and work and rest habits, adjust their emotions, learn to release pressure and appropriate relaxation.