I sure know about dehydrating! My boyfriend and I go to a lot of music festivals in the summer time all over the country (we're big Dead Heads). We camp and spend the whole day baking in the sun and grooving to the music. But I've been pretty beat by the heat at times and I've found a few things to work better than others. As far as fluids go, Gatorade works better than water b/c it helps replenish the sodium that we loose in our sweat. For places where I can't bring a full container in, I bring packets of it to mix with water. Pedialyte is good too. Neither have too much sugar and both provide electrolites. Remember to bring some high protien snacks, I like Luna bars, they taste great! It can be hard, especially on vacation, but limit sodas. Go for lemonade when you're walking in the park. Something as simple as wearing a hat can make a huge difference for me.Have fun,Debbie 22 yr old w/ CFdon't forget the sunscreen!