Dehydration is a condition in which a person losses more fluids than the necessary to maintain correct functioning of the organism. Being a physiologically regulated balance, dehydration occurs when there is an alteration in the balance, due to a decrease in fluid intake or an increase in fluid losses by the body. Dehydration can be qualified as mild, moderate, or severe, depending on the amount of fluid lost and not being replenished, the condition being severe and life-threatening. Effectively a person can suffer from dehydration being the latter caused by two different processes but in the end provoking a similar condition: hydroelectrolytic imbalance. Sometimes the lack of fluids may be due to a reduced intake of water due, for example, to nausea, loss of thirst and appetite related with an illness etc. However, these causes usually represent a small percentage of dehydration cases and usually don’t lead to a moderate or severe case. Finally, the other process responsible for the lack of fluids in the body is the excessive loss of water caused by: excessive sweating, fever, polyuria, vomiting and / or diarrhea.

Dehydration is not a serious problem in adolescents as it can became for infants or young children. Small losses of fluids are not a problem and, in most of cases, go completely unnoticed. Still, not drinking enough liquids to replenish fluid losses can affect the general condition of the body.