One of the first things that happens when the body undergoes the stress response is that blood is diverted away from your digestive tract to your large muscles. Stomach and intestines may empty their contents, preparing the body for quick action.
Many people experiencing stress, anxiety, and nervousness also experience stomach cramps, nausea, vomiting, or diarrhea. (Doctors used to call this “a nervous stomach.” Indeed!)
Long-term episodic or chronic stress has been linked to a number of digestive maladies, from irritable bowel syndrome and colitis to ulcers and chronic diarrhea.