Sudden sitting up while sleeping is related to long-term mental stress, cardiac insufficiency or restless legs syndrome. 1, long-term mental stress, excessive emotional tension, long-term in a state of tension and exertion, it is possible to suddenly sit up when sleeping. This situation needs to be regulated through life, relaxation, work and rest. 2, cardiac insufficiency, if you suddenly sit up in your sleep, accompanied by chest tightness, shortness of breath, hypoxia, cyanosis, sedentary respiration and other symptoms, you need to consider cardiac insufficiency, and may even cough up pink foamy sputum, you need to go to the hospital in time to see a doctor. 3, restless legs syndrome, if you suddenly sit up while sleeping, but there is no chest tightness, shortness of breath, oxygen and other symptoms, it may be restless legs syndrome. Restless legs syndrome most of the sleep at night, the appearance of both lower limbs have difficult to name the sensory abnormalities and discomfort, the patient can sit up or get up, there is a strong desire to move both lower limbs, the symptoms are usually relieved after the activity, and then reappear again after the cessation of the symptoms.