When I was in the Army and in the desert I had a senior NCO tell me that if my men were not peeing they needed to be drinking. It is obviously not possible to drink during the game, but every inning you need to make sure that you have water. I always do the Gatorade or sports drink thing between games and then a lot of water during.
Of course today I leave for Ohio where the high was 80 yesterday after working in 105 all weekend. I will be wearing a jacket every morning, and loving it!