Abstract
Abstract: Water and electrolytes must be balanced between the intracellular and extracellular compartments, and many physiologic mechanisms control this balance. Water is lost through various routes. There are various sources of water intake from food and beverages. Although there is still no standard method for measuring water balance, measurement of body weight changes, measurement of urine concentration such as specific gravity and osmolality, determination of plasma osmolality, and physical examination are common clinical and research assessment methods. The US Food and Nutrition Board's recommended fluid allowances are 3.7 and 2.7 L/d of total water for adult men and women, respectively. It is possible to meet this allowance from a mixed diet of foods and beverages, with or without plain drinking water. Although interest in hydration in healthy individuals is increasing, more research is needed for science-based recommendations for optimum health.