The Importance of Water
Water is one of the most important "equalizers" of the body. It is found in the blood, tissues, the spaces between cells and affects nearly every aspect how a healthy body functions. Since the body cannot exist without water, it has a number of built-in mechanisms that ensure that the body continues to get the water it needs.
Water in the blood helps to maintain adequate blood pressure and circulates important "electrolytes," nutrients and vitamins throughout the body. When large water losses occur by uncontrolled bleeding, the arteries constrict and the heart works harder to continue delivering blood to the body. During temporary water loss, the body can "borrow" water from "intravascular" sources (from inside the blood vessels) and shift it to "intracellular" spaces inside the cells or from "interstitial" spaces that occur between the cells.
Causes of Dehydration
Dehydration can occur anytime there are abnormal demands placed on the body. Under normal circumstances, people lose water while exhaling humidified air, sweating or urinating and having bowel movements. During heavy exercise or in humid weather conditions, the body loses an abnormal amount of water in an effort to regulate body temperature. A high intake of caffeinated beverages, taking diuretics, prolonged vomiting and diarrhea can also lead to dehydration. Diabetics can lose significant amounts of water through the urine in the body's response to elevated blood sugar. Burn victims often experience dehydration because water is shifted from the general circulation to care for the wounds. In certain countries where there are no potable water supplies, people experience profound water losses that eventually leads to dizziness, disorientation and ultimately death.
There are two principal responses by the body when dehydration occurs. The first, and most noticeable is thirst. The second is decreased urine output. When drinking water fails to placate thirst and there is low urine output, people may go on to experience sustained dry mouth, loss of the ability to sweat and produce tears, muscle cramps, lightheartedness when moving from a sitting to standing posture and severe muscle cramps. Other symptoms that occur with prolonged dehydration are rapid heart rate, mental confusion, general weakness that can lead to complete organ failure or coma if left untreated.