Water deprivation kills faster than lack of any other nutrient. In fact without it, a person will be dead within 5 days. Water serves as the body's transportation system. Water is the means by which other nutrients and essential elements are distributed throughout the body. Another vital function of water is its ability to remove waste material from the body.
Water is a lubricant.
The presence of water in and around body tissues helps defend the body against shock. The brain, eyes and spinal cord are among the body's sensitive structures that depend on a protective water layer. Water regulates body temperature. Our health and well-being are dependent on keeping body temperature within a very narrow range. The human body, which is made of 60-75 percent water, serves this function quite well.