Symptoms: You may experience cramping, flatulence, diarrhea during or after running.
Causes: The cause may be dietary in nature or due to lack of blood flow during digestion (since the blood is being pulled to your muscles). You may also have irritable bowel syndrome or lactose intolerance, the effects of which are enhanced by exercise. Dehydration and low electrolyte levels may also lead to diarrhea.
Prevention: This issue is more common in beginner runners, so it may disappear as you become more fit. Try these strategies and see if they make a difference:
- Avoid high-fiber foods (fruit, vegetables, legumes, whole grains) and coffee/tea before working out. Try to drink 64 oz of water every day. You'll know you're well-hydrated if your urine is a light yellow color.
- Consume a sports drink (like Gatorade) during long runs to maintain electrolyte levels.
- Choose foods that are naturally constipating, such as bananas, plain bagels, rice, oatmeal and pasta.
- Make sure you don't eat at least two hours before running, so you give your body plenty of time to digest.
- Try to keep track of what you eat before your runs, so you can figure out possible triggers. For example, some people find that dairy products cause diarrhea.
- Plan your long runs along routes where you know bathrooms are accessible. If you face this problem on race day, don't worry. Most races, especially longer ones such as marathons, offer plenty of port-a-johns at the start and along the race course. In most cases, you can find them near the water stops.
- If you try different tactics and nothing seems to work, you may want to consider a medical check-up for irritable bowel syndrome.