Dehydration 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. Diarrhea may be caused by a bacterial or viral infection, food sensitivity, a reaction to medications or a bowel disorder.
  • 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 may be due to undiagnosed or uncontrolled diabetes. Certain medications, such as diuretics and some blood pressure medications, also can lead to dehydration, generally because they cause you to urinate or perspire more than normal.
Feb. 12, 2014

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