Increased vagal tone can be caused by stress, fatigue, poor sleep, etc. The vagus nerve is an autonomic nerve in the body that is not regulated by the individual. The vagus nerve is an autonomic nerve in the body that is not regulated by the individual. Vagal hyperfunction, i.e., increased vagal tone, can occur in cases of stress, fatigue, and poor sleep. Increased vagal tone will result in bradycardia, weakened myocardial contractility, decreased cardiovascular blood output, and will easily lead to atrioventricular block, while increased gastrointestinal motility will easily cause abdominal distension, diarrhea, and indigestion, which will lead to nutritional deficiencies and gradual emaciation. In general, increased vagal nerve tone is not a pathological problem, and vagal nerve tone changes frequently. Patients can adjust it by regulating their emotions and paying attention to rest, etc. When the symptoms are serious, they should seek medical treatment.