Water, Water – Why You Might Want to Think About It

We are made of water. Arthur Guyton ‘s Textbook of Medical Physiology states that “the total amount of water in a man of average weight (70 kilograms) is approximately 40 litres, averaging 60 percent of his total body weight. In a newborn infant, this may be as high as 75 percent of the body weight, but it progressively decreases from birth to old age, most of the decrease occurring during the first 10 years of life. Also, obesity decreases the percentage of water in the body, sometimes to as low as 45 percent”. (Guyton, Arthur C. (1991). Textbook of Medical Physiology (8th ed.). Philadelphia: W.B. Saunders. p.