Over 50 percent of an adult’s body is water; that figure goes as high as 75 percent in an infant. Blood is 80 percent water and even muscles are 70 percent water. The waterway flows through your body, delivers nutrients to cells and carries away waste. Water acts as your body’s cooling system, moving heat to the skin surface where it evaporates away in sweat and breath. Water lubricates joints, softens skin, and makes muscles work more smoothly. If your body is temporarily short of water – a condition called “dehydration” – every organ in your body is affected.