And most of us don't drink enough, Merriman says. Most people realize they aren't drinking enough water, says Barbara Levine, director of human nutrition at Rockefeller University in New York City. But they may not realize the effects of dehydration. Dehydration can lead to headaches, indigestion, dry skin, poor muscle tone, joint pain, and general toxicity. The body loses about 10 to 12 cups of water each day, even during sleep, so it's essential to replace the lost fluid.
Water leaves the body during normal respiration, in sweat, and body wastes.
By the time we recognize thirst signals, we're already becoming dehydrated. The best way to stay hydrated is to simply drink water. If that's unappealing, try jazzing it up with lemon, lime, or a dash of fruit juice. Avoid beverages such as tea, coffee, and soft drinks. Caffeine, a diuretic, depletes the body of water.