P.U.

One thing that outdoor running holds over treadmill running is fresh air. It seems that within the running community there are a number of GI issues. I will be the first to admit that I toot a little more when I run than when I'm not running (if I ever run outdoors with you, it WILL be prefaced with "Just so you know, I fart when I run." But if we're side by side on a treadmill I won't dare warn you unless there are only two treadmills or we're the only two in the building, otherwise it could be ANYONE). GI issues or not, it makes sense-- things get jostled up and moved along. In this regard, treadmill running stinks... literally. The only thing worse than fighting tooth and nail for cardiovascular health on a treadmill is trying to do so when it smells like epic poo all around you. Everyone has been the culprit (and if you haven't then you're lying), but it doesn't make it any more tolerable when you're the victim. Perhaps one more reason to run outside. Perhaps.