Running and Lower GI Problems

Running is far more likely to cause lower GI issues (diarrhea) than exercises such as swimming, cycling or walking. This is probably due to the physical motion that jogs the contents of the digestive system up and down. A higher Cadence might help with this.

1 General Suggestions

• Eating can trigger the Gastrocolic reflex to defecate. This reflex can cause problems when running, but it can also be used to empty the GI before a run.
• Keep a food diary to detect any patterns in the foods eaten and the problem.
• Try cutting out different foods for a few days to see if they are the source of the problem. I found I was soy intolerant, which gave me indigestion when I ran.
• What works on one run may cause problems on another, but it may be that a food triggers a bout of diarrhea rather than being the underlying cause.
• Seek help from a nutritionist.
• Consider checking with your doctor about Irritable Bowel Syndrome, parasitic infection such as Giardia or other medical issues.
  • If you drink untreated water, you may contract Giardia, which causes diarrhea. The incubation period for Giardia is 6-15 days, so the affect will not be immediate.
• If you are not ‘regular’ (i.e. at least daily) it may help to review your diet to increase your fluid intake, increase your Fiber intake or reduce anything that may ‘bind’.

2 Specific Suggestions

• Try limiting high Fiber foods the 24 hours before a long run.
  • Alternatively, more Fiber may actually help. More Fiber may help the GI tract to empty in a timely fashion (i.e. before the run). For instance, taking some Fiber the night before could help the GI tract empty the next morning before the run.
• Stimulants such as Caffeine and Chocolate (Theobromine) can stimulate or irritate the GI tract. Taken before the run they may help to empty the GI tract, but on a run they may cause problems.
• Avoid using NSAID drugs such as Acetaminophen (Paracetamol) or Ibuprofen as these can irritate the GI tract, especially in higher doses. See NSAIDs and Running for more details.
• Clothing or fuel belts that are tight around the stomach could aggravate the problem.
• Not eating anything before running works for some runners.
• Taking electrolyte supplements such as Endurolytes have been reported to help some runners.
• Taking Probiotics, such as Acidophilus which is found in live Yoghurt may help digestive health. If you have concerns over dairy, probiotics can be taking in other forms such as Miso or supplements.
• Magnesium supplements commonly cause diarrhea, and I know of cases where taking the supplement up to 24 hours before the run still causes problems. Magnesium Oratate does not have the problems that other forms of Magnesium do.
• Following a liquid diet for 12-36 hours before a race may help.
• Carry toilet paper and/or moist wipes with you when you run. A Ziploc snack bag is idea for this purpose to keep the toilet paper dry or the moist wipes wet. An alternative to toilet paper is to use paper towels, which maintain their structural integrity when wet. I would suggest everyone does this on remote races ‘just in case’.
• Staying hydrated may help. There are reported cases of Ischemic colitis, which is inflammation and injury of the large intestine due to restricted blood flow that are suspected of being related to chronic dehydration. See Practical Hydration and The Science Of Hydration.
• Using a Fleet Enema before running may help, but read the warnings carefully and use with caution. http://www.drugs.com/mtm/fleet-enema.html
• Using an anti-diarrheic such as Imodium (Loperamide) helps some runners. However other runners have found that it does not prevent the urge, only the action, which can make the problem worse. Some runners use Imodium as a preventative measure. Remember that taking any drug when running long distances involves risk and Imodium is an opoid drug, though it does not affect the central nervous system.

3 Specific Foods

• Fructose can cause diarrhea as well as bloating and flatulence. This is more of an issue when Fructose is consumed in isolation than when taken as sucrose. (Sucrose is a molecule of Fructose combined with a molecule of glucose.)
• Dairy foods can cause GI problems in sensitive individuals.
• Try avoiding Gluten as you may have a Gluten intolerance. This is particularly important as many of the foods that are used for Carbohydrate Loading are high in Gluten.
• Avoid foods that cause flatulence such as beans.
• Spicy foods containing Capsaicin from Chili peppers can trigger diarrhea some hours after consumption.
• Sorbitol and some other artificial sweeteners can cause diarrhea as they are not digested.
• Avoid ‘fat free fats’ such as Olean Olestra), which are fats that the body cannot digest. These fats can trigger Steatorrhea which involves excess fats in the feces.
• Aloe Vera Juice may help.