Please take what follows as nothing more than a starting point for myself and a collection of randomness from a non Doctor or medical person, do your own research as what is right for me more than likely will not be right for you. What I am posting about here is from Karl King's cheat sheet on hydration for more information.
With regards to hyponatemia, I don't believe I have ventured there during my races but I did used to increase my water intake before marathons and in the process pretty much flushed all electrolytes out of my system. Once I recognized this, I simply made sure if I was going to increase the fluid intake to stay in balance on the electrolytes. That helped but I still had issues with my stomach and hand swelling.
As I worked my way through not flushing out all of my electrolytes, I of course veered the other direction and headed towards dehydration by not consuming enough fluids and then when I thought I did my system would still seem to shut down on the processing of the fluids. After many years of trying to figure out why and blaming my training, Gu's and many other things, I still would end up running with stomach cramps on any hot day (and some mild days) which led throwing up during some events and after a few. I would normally try (or I would have) to slow down to avoid throwing up on the course. I finally discovered the magic of S-Caps. One of the first marathons I had some success at was in 2007 in Kansas City, it was a fairly hot day and I used S-Caps and I got through the day without major issues. Since then, I have yet to throw up again but I still have had issues.
At McNaughton, after reviewing Karl's chart, I am pretty sure I was one of the following two stages
Hydration: Normal - Electrolytes LOW
- Weight is normal
- Stomach is queasy, with poor food acceptance
- Wrists may be puffy
- Salty foods taste good
- Thirst is normal
- Mouth is moist – can spit
- May have cramping
- Causes: Insufficient electrolyte intake
Hydration: LOW Electrolytes OK - Dehydration Likelihood: common
- Weight is down a few pounds or more
- Thirst is high, and salty foods taste normal.
- Mouth is dry, food acceptance is poor
- Skin is dry and may tent if pinched
- May have dizziness on standing up
- May have cramping
- Mental performance may be affected
- Causes: insufficient fluid intake
Having reviewed the two, my guess is the first, I did ok on the hydration but my electrolytes got low as I am fairly convinced that I do sweat out a lot of salt and I failed to take in enough S-Caps. I never like to take pills of any sort and am always afraid with S-Caps that I might take in to many. My normal consumption is one per hour or one per 3/4 hour never any more often unless I have stomach cramps then I will take one.
So on our last longish run before Lincoln I decided to increase my S-Caps to about 2 per hour and I had almost no hand swelling and felt fine with no ill effects afterward. In reading, 2 per hour is not out of line on a warm or a hot day and may be what I need to take in all of the time. Since I almost never use the bathroom during the race, I think I am ok with this quantity, I should add that my post run weight is almost always lower by a few pounds or more.
So on to Lincoln to continue the experiment.