I just completed my second marathon this past weekend. Since the conditions were very warm,(ranging from 65-85 degrees, and I should mention I live in the mountains and have not trained in any heat this year)I consumed water at every stop and Powerade at every other stop. Here is the problem: After the race I continued to rehydrate. In about two hours and a gallon of water later, I realized I still had not urinated and did not for a couple more hours. My stomach also swelled up as if I had overeaten and I did not feel well at all, for example, dizziness and very exhausted. I have heard about the GI tract shutting down but is this a sign of kidneys and bladder also shutting down? Or is this condition a symptom of over-heating or running too hard? I am doing another marathon next month would like to know how to prevent a reoccurence.Thanks!
CG - One of the biggest problems we see in the sports medicine trailer at the end of road races is dehydration. I can't emphasize enough how important it is to start the race properly hydrated. In fact, most people are moderately dehydrated, and even if one tries, it is hard to properly hydrate, more so if one exercises regularly. Once dehydrated, is is really difficult to rehydrate while exercising. Drinking water only allows rehydration to about 60% (the bladder makes urine, and drinking water quenches the thirst). Drinking sports drinks allow rehydration to about 80% (BUT, be aware of the amount of sugar you are taking in - some are quite a bit more loaded with sugar than others, and in fact, you could cut the sports drink with water to get a better ratio).
The key is to avoiding the dehydration you experienced (I agree that your systems shut down), is to make sure you hydrate fully every day, and to over hydrate, or hydrate load, just as you would carbo load, the week prior ot a race. At first, you will want to pee a lot, but as you reach a homeostatic balance reduce your, need to urinate will decline, and you will enter the next marathon much, much more hydrated, and less likely to repeat the experience.