When I run, I get the runs! Yesterday, during a ten-miler, I had to stop twice to relieve myself even though I had a bowel movement prior to leaving home. This is becoming a serious concern, as it seems to affect all my runs. Have you ever heard of this problem? Is there a solution that does not involve medication? - Seeking Movement Improvement
I may not be a "medical expert" on the subject of digestive health, but I am human, thus I have all of that complicated tubing, glandular organs and assorted squishy guts needed to process solid food into solid waste. Further, as a runner, I find that my constant reward for all the miles I put in each week justifies my consumption of greater quantities of food than my neighboring stationary beings. So, I eat a lot.
The answer to the question you ask should not only resolve your issue of "waste management", but should equally address a proper "fuel strategy" for distance running. For a 10 mile run, you have to eat something, but practice and the tips I will propose to you here, should minimize your bodies attempt to "unload" during your runs.
First, as with comedy, and asking a girl to dance: timing is critical. It takes time for your body to break down food into disgusting little nuggets, so give it a chance. I usually eat a high carbohydrate meal no later than 6:00 pm at night. (Generally I eat something a little starchy like pasta or rice, the higher glycemic the better). This gives your body a chance to absorb lots of sugar producing "carbs" while at the same time processing the excess waste you will need to discharge in the morning.
So, rule number one: eat dinner no later than 6:00 pm, and eat no other solid food after 6:00 pm. (Drink all the fluids your little bladder desires however, go crazy).
Secondly, when you wake up, have a cup or two of coffee. Now, I know that a lot of runners get obsessive and avoid ingesting so called "diuretics", because they tend to dehydrate the body, but honestly, our entire society is addicted to the warm delicious goodness of java, so don't deny yourself. Besides, coffee tends to help loosen up the lower digestive tract, and that means quality bathroom time. A general rule says that you should attempt to "void" yourself three times prior to your long run, but the key to this action is quantity, not quality. Coffee can help you meet this goal. Drink up.
Rule number two then is: drink a cup of coffee, or tea, or maybe even a caffeine-laden soda. Caffeine is a diuretic, and that helps you to move that bowel.
Tip number three is to have a light breakfast two hours before your long run or race. If your race is at 10:00 am, have a banana, bagel or energy bar no later than 8:00 am. This helps to "top off" your blood supply with simple sugars (the fuel you will need) and allows your digestive system to process whatever is left in your stomach. It takes the average person an average of two hours to digest most foods. This will get you to the start of your run feeling "full" without being "bloated".
So, rule number three is to eat a small carbohydrate based breakfast no less than two hours before your run.
If you follow these simple rules, there is a good chance you will resolve your "unscheduled unloading" problem. Of course, everyone digests differently, so you will have to experiment with these guidelines, but generally speaking if you carefully monitor your intake of food from the night before up to the start of your run, you will have given your body the fuel it needs to accomplish the mighty task before it subjecting it to an untimely "movement" of bodily waste.
Run long and taper.