Volume Control in the Desert: Stone Formers in Saudi Arabia
In Saudi Arabia, temperatures for most of the year can range between 30–50°C and the relative humidity between 4–7%. As a result, a considerable loss of salt and water occurs through the sweat glands and air-ways. In the desert on a dry hot day, for example, a man can lose 10 to 12–1 of water in an attempt to maintain thermal control. A daily loss of 2–1 of sweat is common in most individuals living in this environment. Unless such losses are replaced, urine volume drops rapidly in an attempt to maintain the ECFV. In such a situation, precipitation of salts in a concentrated urine can occur, leading eventually to stone formation.