How much liquid should you take during a long run or race? To know this you need to know your "sweat rate." Weigh yourself nude before a training run, and then again after. 1 pound of weight loss = 1 pint of water loss. If you lose 2 pounds after running for an hour that is equal to 2 pints of water (or 32 ounces). Therefore you need 8 ounces of water for every 15 minutes you run (on a 60 minute run).