Over-hydrate? Is that possible?

The first time that I came across the idea that a person could overhydrate was during a SCAN educational session I went to. In my prior exercise physiology classes I had been taught about all the dangers of dehydration and the impact that dehydration has upon performance, but overhyration seemed foreign.

During the session, Bob Murry, Ph.D talked about proper hydration and why a "water only" hydration plan, was not always safe, especially in ultra-distance events. The thing that brought home the message was a set of before and after photos of a lady completing an Ironman event. If I remember right she had gained over 20 pounds! (I don't remember the exact stats, but it was a lot.)

I have come across two different blog posts this month that have discussed hydration and weight gain in an ultra event. (Post one.) One of those blog posts was an interview posted today with Brian Morrison about his Western States 100 finish.

It raises the question: How do you find the proper solution of water and electrolytes (and carbs for energy) to use when competing in an ultra event? I don't have any great tips in fine tuning this process.... so hopefully some of you can help out.

For now, check out the Gatorade Sports Science Institute website. It has a lot of good research and info on the subject.