You can survive for a month without food, but only a few days without water.
Water is the most important nutrient for active people.
When you sweat, you lose water, which must be replaced. Drink fluids before, during, and after workouts. Water is a fine choice for most workouts. Sports drinks have two very important ingredients - electrolytes and carbohydrates Sports drinks replace electrolytes lost through sweat during workouts lasting several hours. Carbohydrates in sports drinks provide extra energy.