Prevention and Treatment
Where possible, it is best to prevent dehydration by drinking adequate fluids, especially when losing water through perspiration, and making up for losses as they occur. Those involved in extended physical exertion, for instance, should make sure that they drink water before, during, and after their activities. The equivalent of 8 glasses of fluids per day for women and 12 glasses of fluids per day for men (including that derived from foods with high water content – vegetables, fruits) is adequate to maintain proper hydration.
Mild dehydration can be treated in most healthy adults by drinking more water. Moderate to severe dehydration can be more complicated to treat, especially if there is also an electrolyte imbalance with excess or a deficient sodium (hypernatremia or hyponatremia) level. With moderate to severe dehydration, plain water is usually insufficient because it will not restore a person's electrolyte balance.
Oral rehydration solutions (ORS, commercially available under a variety of brand names) that contain small but very specific concentrations of salt and sugar are often used to slowly return a person's fluid and electrolyte balance to normal. ORS are NOT the same thing as, for example, sports drinks, energy drinks, or flavored waters; the types and proportions of ingredients are different.
There can be serious complications, such as fluid accumulation in the brain (cerebral edema), if someone is significantly dehydrated and rehydration is done too rapidly. In addition, someone who has been vomiting may have difficulty retaining large amounts of fluid. Typically, very small amounts of fluids are given frequently, such as every few minutes for several hours, and the person's health status is monitored.
In some cases, a person may need to be hospitalized and have intravenous (IV) fluids administered, with careful monitoring until both fluid and electrolyte balances are restored.
For some individuals, an underlying condition that causes vomiting, diarrhea, and/or other problem exacerbating dehydration will also need to be addressed.