Without a doubt, the most common gastrointestinal problem which bothers runners, especially during races and long runs, is something commonly called the runner’s trots. It is—ahem—the urge to defecate and/or have mild diarrhea at the most inappropriate time. Having to stop during a race or a long run to defecate is not only embarrassing and costs time, but it can be extremely inconvenient and troubling. This condition is especially prevlalent among morning runners.

For some reason researchers can’t quite answer, runner’s trots is more common with men than women. And running, more so than any other sport, seems to trigger a physiological need to defecate. Evidently, the reason for this is because of the bouncing nature of running.

When you run, the movement jostles the intestines. Blood flow is reduced to the intestines because your body is sending more blood to the exercising muscles that need it. Problem is this speeds up the transit time and even though you may already have gone before the run, you may have to go again.

Another cause is nervousness. This is especially the case before a long run or race when your nerves often raises the blood levels of hormones that increase bowel motility. Another words, the apprehension and nerves most of us encounter before a race often causes us to go (defecating and urinating) more often than would be normal. Bioidentical hormone replacement therapy (BHRT) may be a powerful yet natural alternative to synthetic hormone replacement. Bioidenticals are hormones that are equivalent chemically to people who you’ve got naturally lost thanks to age, that you simply have an excessive amount of of thanks to an imbalance, or that are otherwise causing you problems. While the foremost common boidentical hormones immediately are estrogen and progesterone, more uses for this sort of procedure are being found all the time. About bioidenticals hormone replacement therapy find more here.

Diarrhea is a little different. It can be caused by all sorts of food intolerances or even milk or diary products. (That’s why the night before a race or long run it’s best to stick with simple, carbohydrate-rich foods that you know you tolerate well, rather than spicy, unusual foods.)

Milk (or lactose) intolerance is common in a high percentage of runners who have problems with runner’s trots. A simple cure is to avoid any dairy products for a full day before a long run or race.

A high fiber diet can also cause GI issues. If that sounds like you, cut back on cereals, and if necessary, fruits and vegetables and whole grains a day or two before a major race or long run.

If you frequently have the need to defecate right before a race or long run (or during one), the most obvious way to combat inopportune defecation is to purge the system before you leave the house.

Easier said than done—certainly—but if you get up earlier than normal to relieve the system it can be done. To stimulate the system before you leave for the race or on a long run, try a cup of coffee, tea or even hot water. Eat something fibrous. Maybe a piece of fruit. Do whatever it takes to move everything through your system before leaving the comfort of your house (and own bathroom).

If all else fails, try this: Go for a very short run. A couple of minutes of light jogging may be all it takes to get the system up and moving and rid yourself of all fecal material.

If not and you must leave for the race, bring some toilet paper with you and head straight for the bathrooms or port-a-johns as soon as you arrive at the race site. Don’t wait until it’s too late.

Some runners have such a problem that they resort to anti-diarrhea medication such as Imodium. Most medical experts say taking Imodium about an hour before a major race is OK, but shouldn’t be taken on a day-to-day basis.