In fact, the human body can last only a few days without it. For an adult with a healthy heart and kidneys, eight glasses of water a day has always been recommended to promote good health. To keep your body from becoming dehydrated, a person should drink an ounce of water for every two pounds of their body weight. Someone who weighs 180 pounds should drink 90 ounces of water daily. The equivalent of 10 glasses is lost in a day through perspiration, urine and respiration.
Additional losses occur during vigorous exercise.
Dr. Gore said that water is essential for regulating body temperature, cushioning joints, providing circulating volume for transporting nutrients throughout the body, building body tissue, digesting food and ridding the body of wastes. Water also helps prevent dry skin, constipation, urinary tract infections and kidney stones. A good way to take in all of the recommended water is to drink one glass when you wake up each day, one at each meal, another between meals and another before going to bed. The recommended eight glasses don't necessarily have to be water, according to Dr. Gore. Not recommended are those that contain caffeine or alcohol which, because they have a dehydrating effect, require even more water to compensate for the fluid loss.