The reasons for diarrhea after running include lack of exercise, excessive tension or improper diet before exercise. 1. lack of exercise: usually lack of exercise, sudden exercise can cause gastrointestinal dysfunction caused by diarrhea, it is recommended to reduce the amount of exercise. It is recommended to reduce the amount of exercise properly and then gradually increase the amount of exercise after slowly adjusting. 2. Excessive tension: due to mental tension caused by gastrointestinal discomfort. It is recommended to pay attention to rest, pay attention to abdominal warmth, do not catch a cold, and keep a calm mind. 3. Improper diet: such as eating stimulating food before exercise, such as hot pot or cold food such as ice cream, exercise leads to increased gastrointestinal peristalsis and cause diarrhea. You should eat a light diet before exercise, or exercise after half an hour after a meal. Diarrhea may also be caused by other reasons, if diarrhea aggravated without relief, should promptly consult a doctor, under the guidance of the doctor for targeted treatment. Please do not take medication on your own to avoid delaying your condition.