In general, diarrhea after strenuous exercise may be caused by inhaling too much cool air, or it may be caused by irritable bowel syndrome and other reasons. 1. Cold: When you exercise vigorously, you may inhale too much cool air, which stimulates the gastrointestinal mucosa and causes an increase in gastrointestinal peristalsis, leading to abdominal pain, diarrhea and other symptoms. 2. Irritable Bowel Syndrome (IBS): a common dysfunctional disorder that manifests itself as abdominal pain or abdominal discomfort, accompanied by changes in bowel habits and traits. After strenuous exercise, increased intestinal peristalsis or intestinal spasm can induce or aggravate the diarrhea symptoms of irritable bowel syndrome, resulting in the above situation. Diarrhea after strenuous exercise may also be caused by peptic ulcer, chronic enteritis and other causes, it is recommended to consult a doctor in a timely manner, under the guidance of the doctor to clarify the cause of the disease, targeted treatment.