Why do runners get the runs? Well all that bouncing and jostling is bound to do something to your stomach. Plus the fact that when you are exercising, blood flow is increased to the muscles that are working hard. That means blood flow is taken away from your intestines and such. If they are still trying to digest, this could be a problem and they may not be able to digest properly. However, the exact cause of the so-called "runner's trots" is not really known.
What can you do about it?
Well....you could invent a running toilet and make it run everywhere with you! There's been many a time I wished I had this :)
You can visit those super creepy nasty looking outhouses that you find in the woods randomly....
But those probably aren't the best solutions.
First you should analyze your diet. Is what you're eating before a run causing you to get the runs? Do you eat too close to running or too early before a run? This takes trial and error to find out what works for you. Yogurt is good for the stomach because of the active bacteria in it. But, dairy is usually really bad so you have to find out if yogurt will help you or not. I know that I need to be done eating at LEAST an hour before I run, but not more than 2 hours before I run. When I run on an empty stomach I often feel just as sick as when I run on a full one. As a runner with gluten intolerance it has taken me a long time to find out what I can and can't eat before a run.
Another solution I have discovered is to tie toilet paper in my shoe laces because sometimes, no matter what you do, you just can't help what happens to your stomach on a run. Yes, I look like a dork. But I can't tell you how many times my teammates have asked me for a square or two :) Now you may think that is a little gross because the TP can get dirty, but only the top layer and you know what? I bet its a lot cleaner than whatever branch or leaf you would otherwise use.
|Sorry for the poor picture quality. I cannot locate my camera at the moment.|
If you only run in densely populated areas and neighborhoods then packing toilet paper with you probably isn't going to be very helpful. This is when you will have to plan your route ahead of time knowing where there will be bathrooms you can use. As you get to know your body you will find that "that time" usually comes around the same time during every run (e.g. after 15 minutes or after 25 minutes, etc.) As you learn this you will be able to plan your route accordingly.
Hope this post was helpful and not too distasteful :) There is no shame in being a true runner! I'm sure you marathoners and ultra runners know all about this! Feel free to comment with any funny stories or other tips!
For a little more info on why this happens check out this short article: http://www.runnersworld.co.uk/general/qa-why-this-post-race-toilet-problem/1538.html