Add some stress, pre-event jitters, high intensity effort--and it's no wonder athletes (particularly novices whose bodies are yet unaccustomed to the stress of hard exercise) fret about "runners' trots."
Exercise--specifically more exercise than your body is accustomed to doing--speeds up GI transit time. (Strength- training also accelerated transit time from an average of 44 hours to 20 hours in healthy, untrained 60-year old men.)
As your body adjusts to the exercise, your intestines may resume standard bowel patterns. But not always, as witnessed by the number of experienced runners who carry toilet paper with them while running. (They also know the whereabouts of every public toilet on the route.) Athletes with pre-existing GI conditions, such as irritable bowel or lactose intolerance, commonly deal with runners' trots.
Solutions for Intestinal Rebellion
To help alleviate undesired pit stops, try exercising lightly before a harder workout to help empty your bowels. Also experiment with training at different times of the day. If you are a morning runner, drink a warm beverage (tea, coffee, water) to stimulate a bowel movement; then allow time to sit on the toilet to do your business prior to exercising. When exercising, visualize yourself having no intestinal problems. A positive mindset (as opposed to useless fretting) may control the problem.
The following nutrition tips might help you fuel wisely and reduce the symptoms:
1) Eat less high fiber cereal. Fiber increases fecal bulk and movement, thereby reducing transit time. High fiber = High risk of distress. Triathletes with a high fiber intake reported more GI complaints than those with a lower fiber intake.
2) Limit "sugar-free" gum, candies and foods that contain sorbitol, a type of sugar that can cause diarrhea.
3) Keep a food & diarrhea chart to pinpoint food triggers. For a week, eliminate any suspicious foods--excessive intakes of juice, coffee, fresh or dried fruits, beans, lentils, milk, high fiber breads and cereals, gels, commercial sports foods. Next, eat a big dose of the suspected food and observe changes in bowel movements. If you stop having diarrhea when you cut out bran cereal, but have a worrisome situation when you eat an extra-large portion, the answer becomes obvious: eat less bran cereal.
4) Learn your personal transit time by eating sesame seeds, corn or beets--foods that can be seen in feces. Because food moves through most people's intestines in 1 to 3 days, the trigger may be a food you ate a few days ago.
5) Stay well-hydrated. GI complaints are common in runners who have lost more than 4 percent of their body weight in sweat. (That's 6 lb. for a 150 lb. athlete.) Runners may think they got diarrhea because of the sports drink they consumed, but the diarrhea might have been related to dehydration.
6) When all else fails, you might want to consult with your doctor about timely use of anti-diarrhea medicine, such as Immodium. Perhaps that will be your saving grace.