this is from my coaches page - he had a PHD in exercise physiology from Colorado State he has programs that are being used by Lance - so yes...I trust what he says as golden
"About 60-70% of your body is water. Your blood is mostly water and your organs contain water. Water is essential for your body to function. Not drinking enough water puts a tremendous strain on your body as it tries to compensate to the lake of water. As an athlete, it becomes more important since you loose much more water than a sedentary person. Water regulates your body temperature, provides a means to transport nutrients to all of your organs, transports oxygen to your bodies' cells and removes waste. If you take your body weight and half that number, that is the absolute minimum amount of water, in ounces, you should be drinking every day."
"Probably the most important part of race day. Make sure you hydrate sufficiently the morning of race day, your urine should be a pale yellow. If it's yellow or darker you have not hydrated enough, if it's clear you have over hydrated. Over hydrating can result in a dangerous even fatal condition known as hyponatremia.
The age old question, how much should I drink during a race? That depends on many factors, temperature, length of race, body weight, fitness and how much you sweat. A fairly accurate way to determine your hydration needs is to pick a day that has a
temperature similar to the average temperature of your races. Make sure you are adequately hydrated before this workout. Weigh yourself naked on an accurate scale before you start. Complete your workout at race pace for an hour, without consuming any liquid. Immediately following your workout weigh yourself naked on the same scale. If you lost 1 lb (16oz), you need to consume approximately 60% of that for every hour you are racing.
By race start you should be fully hydrated and your glycogen stores should be full. During the race do not rely on thirst as an indicator to drink, by that time you have already started to dehydrate. You should be drinking a little at least every 15 minutes. You should know your hydration requirements in order to avoid dehydration or over hydrating, you need to find the perfect balance. Get to know the symptoms of both. Signs of dehydration include, headache, fatigue, dizziness, nausea, muscle cramps, chills and thick saliva. Signs of hyponatremia include, puffiness, like swollen figures, tight watch, liquid sloshing in your stomach, vomiting, progressively worsening headache.
During races or training workouts longer than an hour you will need to drink some sort of sports drink that contains electrolytes and carbohydrates and as older athletes it becomes more important that drink also contains protein in the correct ratio. "
what you need in the H2O = http://outsidesport.com/H2O%20Enhancer.htm