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U-M Health SystemThis information is approved and/or reviewed by U-M Health System providers but it is not a tool for self-diagnosis or a substitute for medical treatment. You should speak to your physician or make an appointment to be seen if you have questions or concerns about this information or your medical condition.

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Dehydration

What is dehydration?

Dehydration is a loss of too much fluid from your body. The human body needs water to maintain normal functions. If your body loses much more fluid than you are drinking, you become dehydrated. If the loss of fluid is severe, you can become very ill and possibly die.

You lose fluids when you:

  • urinate
  • vomit or have diarrhea
  • sweat
  • breathe, especially when you breathe rapidly
  • overexert yourself in hot or humid weather
  • have a fever.

Along with the fluids, your body loses electrolytes, which are important for normal body functions.

How does it occur?

The usual causes of dehydration are diarrhea and vomiting. Dehydration can also occur if you do not eat or drink much during an illness or if you do not drink enough during or after strenuous exercise. Medicines that control excess body fluid (diuretics, or "water pills") by causing fluid loss are a common long-term cause. Diabetes can also cause water loss if your sugar is too high.

Although anyone can become dehydrated, people who become dehydrated the most easily are:

  • babies less than 1 year old
  • older adults
  • anyone who has a fever
  • people in hot weather
  • people doing strenuous work or activity, especially in the heat
  • people with diabetes if they are urinating a lot because their blood sugar is too high.

What are the symptoms?

Symptoms of early or mild dehydration include:

  • thirst
  • flushed face
  • dry, warm skin
  • small amounts of dark, yellow urine
  • lightheadedness or dizziness made worse when you stand
  • weakness
  • cramping in the arms and legs
  • having few or no tears
  • headache
  • a lack of energy
  • dry mouth and tongue with thick saliva.

When dehydration is moderate to severe, other symptoms are:

  • fainting (caused by low blood pressure)
  • severe muscle spasms in the arms, legs, stomach, and back
  • convulsions
  • a bloated stomach
  • sunken eyes with few or no tears
  • lack of skin elasticity (a bit of skin lifted up takes a long time to go back to its normal position)
  • rapid and deep breathing.

How is it diagnosed?

Your healthcare provider will review your symptoms and examine you.

How is it treated?

If you are dehydrated, you need to drink enough liquid to replace the fluids you have lost. Also, you need to replace the electrolytes you have lost. Drink more fluids right away. Do not wait until dehydration becomes severe. Drinking sips of water slowly, along with eating the typical American diet, which is high in salt, will replace fluids and salts you have lost.

You can also replace fluids and electrolytes by drinking sports drinks or oral rehydration solutions (ORS). You can buy packets of oral rehydration salts at drug and grocery stores. Mix the contents of a packet with 1 quart or liter of drinking water. If you are not sure if the water is safe to drink, first boil the water for at least 5 minutes.

  • Drink sips of the ORS every 5 minutes until urination becomes normal. (It's normal to urinate 4 or 5 times a day.) Adults and large children should drink at least 3 quarts or liters of ORS a day until they are well.
  • If you are vomiting, keep trying to drink the ORS. Your body will retain some of the fluids and salts you need even though you are vomiting. Remember to take only sips of liquids. Chilling the ORS may help.
  • If you have diarrhea, keep drinking the ORS. The fluids will not increase the diarrhea.

If you don't have a sports drink or ORS packet, you can make an oral rehydration solution using the following recipe: To 1 quart or liter of drinking water or boiled water, add the following:

  • 2 tablespoons sugar
  • 1/4 teaspoon salt
  • 1/4 teaspoon baking soda (bicarbonate of soda).

If you don't have any baking soda, add another 1/4 teaspoon of salt. If possible, add 1/2 cup orange juice or some mashed banana to improve the taste and provide some potassium.

Severe dehydration requires immediate medical attention. It is treated with intravenous (IV) fluids (fluids given directly into the veins through a needle). During or after treatment of dehydration, you should also be treated for whatever is causing diarrhea, vomiting, or other symptoms. Changes in medicine and control of underlying illnesses are often needed. Diabetics are particularly prone to dehydration and should see a healthcare provider as soon as possible if they become dehydrated or have a prolonged period of high blood sugar.

How long will the effects last?

If dehydration is not treated, it can cause death. If it is treated in time, recovery is usually complete.

How can I take care of myself?

  • Know the symptoms of dehydration. Try to drink extra fluids if you know your body is losing a lot of fluid. One way to tell if you are drinking enough liquid is to look at the color of your urine. It should be very light yellow.
  • If you have been vomiting and can't keep liquids down, suck on ice chips or flavored ice until the throwing up stops. You may drink more liquids as your vomiting lessens.
  • If you are traveling in a country that may not have safe water for drinking, carry with you a quart (liter) of boiled water and packets or the ingredients for making oral rehydration solutions.
  • Call your healthcare provider or go to the emergency room right away if:
    • You feel faint when you stand up.
    • You keep having nausea or vomiting that stops you from getting enough fluids.
    • You have a fever higher than 101.5°F (38.6°C).
    • You pass very little urine or none at all after 8 hours of treatment.
    • You heartbeat is much faster than usual...
  • Call or see your provider during office hours if:
    • You are feeling lightheaded.
    • You have any other symptoms that worry you.

How can I help prevent dehydration?

Make sure you drink plenty of fluids. When you are physically active, especially in hot weather, it is best to drink water some time before starting the exercise or sport. Then drink small amounts of water often during the exercise. Continue to drink liquids after exercise.

If you have diarrhea or vomiting or you are not drinking much, try to drink more liquids before you become dehydrated.

If you are with someone you think is becoming dehydrated, follow these guidelines when possible:

  • Give more liquids than usual.
  • Remember that a dehydrated person will have less of an appetite. Encourage him or her to eat and drink small amounts of food and liquids 5 to 7 times a day.
  • Watch for signs of more severe dehydration. If you think someone is becoming severely dehydrated, get medical help as soon as possible.
Developed by RelayHealth.
Published by RelayHealth.
Last modified: 2008-08-11
Last reviewed: 2008-03-30
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
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