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Causes
By Mayo Clinic staffDehydration occurs when there isn't enough water to replace what's lost throughout the day. Your system literally dries out. Sometimes dehydration occurs for simple reasons: You don't drink enough because you're sick or busy, or because you lack access to safe drinking water when you're traveling, hiking or camping.
Other dehydration causes include:
- Diarrhea, vomiting. Severe, acute diarrhea — that is, diarrhea that comes on suddenly and violently — can cause a tremendous loss of water and electrolytes in a short amount of time. If you have vomiting along with diarrhea, you lose even more fluids and minerals. Children and infants are especially at risk.
- Fever. In general, the higher your fever, the more dehydrated you may become. If you have a fever in addition to diarrhea and vomiting, you lose even more fluids.
- Excessive sweating. You lose water when you sweat. If you do vigorous activity and don't replace fluids as you go along, you can become dehydrated. Hot, humid weather increases the amount you sweat and the amount of fluid you lose. But you can also become dehydrated in winter if you don't replace lost fluids. Preteens and teens who participate in sports may be especially susceptible, both because of their body weight, which is generally lower than that of adults, and because they may not be experienced enough to know the warning signs of dehydration.
- Increased urination. This is most often the result of undiagnosed or uncontrolled diabetes mellitus, a disease that affects the way your body uses blood sugar. This type of diabetes often causes increased thirst and more frequent urination. Another type of diabetes, diabetes insipidus, also is characterized by excessive thirst and urination, but in this case the cause is a hormonal disorder that makes your kidneys unable to conserve water. Certain medications — diuretics, antihistamines, blood pressure medications and some psychiatric drugs — as well as alcohol also can lead to dehydration, generally because they cause you to urinate or perspire more than normal.
References
- Dehydration. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merck.com/mmpe/sec19/ch276/ch276b.html. Accessed Oct. 27, 2010.
- Diarrhea. National Institute of Diabetes and Digestive and Kidney Diseases. http://digestive.niddk.nih.gov/ddiseases/pubs/diarrhea. Accessed Oct. 27, 2010.
- Popkin BM, et al. Water, hydration, and health. Nutrition Reviews. 2010;68:439.
- Thomas DR, et al. Understanding clinical dehydration and its treatment. Journal of the American Medical Directors Association. 2008;9:292.
- Rodriguez NR, et al. Position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and athletic performance. Journal of the American Dietetic Association. 2009;109:509.
- Montain SJ. Hydration recommendations for sport 2008. Current Sports Medicine Reports. 2008;7:187.
- Manz F. Hydration in children. Journal of the American College of Nutrition. 2007;26:562.
- Canavan A, et al. Diagnosis and management of dehydration in children. American Family Physician. 2009;80:692.
- WHO position paper on oral rehydration salts to reduce mortality from cholera. World Health Organization. http://www.who.int/cholera/technical/en/. Accessed Oct. 27, 2010.
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