As others have suggested, drink lots of water before the ride, during the ride and after the ride. I try to get in 1 - 1.5 liters of water before a hot weather ride (the hot/humid stuff is just around the corner here in Kentucky). I carry two water bottles filled with Gatorade and stick another one in my back pocket. I carry a couple of Clif bars to munch on as well. I also find it helpful to take a brief breaks in a shady spots along the way. Ride your ride, drink and be merry. Good luck.