Drinking plenty of water is important, particularly among people who exercise vigorously. Follow the following recommendations:* Two or three hours before you start to exercise, drink 17-to-20 ounces or half a litre of water.* Twenty to 30 minutes prior to exercise, or while you're warming up, drink another eight ounces.* While you're exercising, drink seven-to-10 ounces or quarter a litre every