Dehydration Health Article

Definition

Dehydration is the loss of water and salts that are essential for normal body function.

Description

Dehydration occurs when the body loses more fluid than it takes in. Dehydration can upset the delicate fluid-salt balance needed to maintain healthy cells and tissues. The human body is generally over 60 percent water. The body works to maintain water balance through mechanisms such as the thirst sensation. When the body requires more water, the brain stimulates nerve centers to encourage a person to drink in order to replenish the water stores. Water intake can vary widely on a daily basis, influenced by such factors as access to water, thirst, habit, and cultural factors.

The kidneys are responsible for maintaining water balance through the elimination of waste products and excess water. Water is primarily absorbed through the gastrointestinal tract and excreted by the kidneys as urine. The variation in water volume ingested is dependent on the ability of kidneys to dilute and concentrate the urine as needed.

Children need more water than adults because they expend more energy, and most children who drink when they are thirsty get as much water as their systems require. Dehydration in children usually results from losing large amounts of fluid and not drinking enough water to replace the loss. This condition generally occurs in children who have a stomach flu characterized by vomiting and diarrhea or who cannot or will not take enough fluids to compensate for excessive losses associated with fever and sweating of acute illness. Dehydration can result from illness; a hot, dry climate; prolonged exposure to sun or high temperatures; not drinking enough water; and overuse of diuretics or other medications that increase urination.

Types of dehydration

Dehydration is classified as mild, moderate, or severe based on how much of the body fluid is lost, estimated by loss in bodyweight. Mild dehydration is the loss of no more than 5 to 6 percent loss of body weight. Loss of 7 to 10 percent is considered moderate dehydration. Severe dehydration (loss of over 10 percent of body weight) is a life-threatening condition that requires immediate medical care.