Water is the most essential ingredient to a healthy life. Our bodies are made up of 65 percent water. Being dehydrated by even 2 percent can decrease performance by 10 percent. Hydration becomes more imperative when you are making up for the water lost in sweat from a good workout. Adequate fluid intake is essential to comfort, performance and safety. The longer and more intensely you exercise, the more important it is to drink the right kind of fluids.