Drank about 6 quarts of water on my 10.4 mile hike in hot humid weather. Around 4:15 moving time. Ate a couple of salty cracker packages. All I know if you are in the heat drink and drink a lot. Not to the point of hyponatremia. Drink enough but not like you are flushing a toilet you will be OK if you stay within the fitness level you are at.