DefinitionBy Mayo Clinic staff
Dehydration occurs when you lose more fluid than you take in, and your body doesn't have enough water and other fluids to carry out its normal functions. If you don't replace lost fluids, you may get dehydrated.
Common causes of dehydration include intense diarrhea, vomiting, fever or excessive sweating. Not drinking enough water during hot weather or exercise also may cause dehydration. Anyone may become dehydrated, but young children, older adults and people with chronic illnesses are most at risk.
You can usually reverse mild to moderate dehydration by drinking more fluids, but severe dehydration needs immediate medical treatment. The safest approach is prevention of dehydration. Monitor your fluid loss during hot weather, illness or exercise, and drink enough liquids to replace what you lose.
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