Symptoms and Complications
The body will attempt to deal with dehydration by first stimulating the thirst centers of the brain, which will prompt someone who is dehydrated to drink more fluid. However, if water intake cannot keep up with water loss, dehydration will become severe and the body will respond by decreasing sweat and producing less urine. People who are adequately hydrated will usually urinate light-colored urine every 3 to 4 hours. Because the water in the bloodstream is very important, the water in and around the cells will begin to move into the bloodstream.
If dehydration continues, the cells in the body will begin to shrivel and malfunction, and tissues in the body will begin to dry out. Because brain cells are among the most susceptible to dehydration, confusion and even coma can occur.
Because of dehydration, the body's electrolytes (dissolved mineral salts such as sodium, potassium, and chloride) may become deficient, and water will not be able to move as easily from inside cells into the blood. The amount of water circulating in the bloodstream will be further reduced and blood pressure can drop, causing light-headedness or the sensation of starting to faint, particularly when standing up suddenly. If water and electrolyte losses continue, blood pressure can fall dangerously low, resulting in shock and severe damage to many internal organs, such as the kidneys, liver, and brain.