What is dehydration?

The human body needs water to maintain enough blood and other fluids to function properly. If your body loses substantially more fluids than you are drinking, you become dehydrated.

You may lose fluids in a variety of ways:

• when urinating

• when you vomit or have diarrhea

• when sweating

• from the lungs during normal breathing.

Along with the fluids, your body also loses electrolytes, which are salts normally found in blood, other fluids, and cells.

How does it occur?

The usual causes of dehydration are a lot of 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. Medications that cause fluid loss to control excess body fluid (diuretics) are a common long-term cause. Although anyone can become dehydrated, those who become dehydrated the most easily are:

• babies under 1 year old

• the elderly

• anyone who has a fever

• people in hot climates.

What are the symptoms?

Symptoms of early or mild dehydration include:

• flushed face

• extreme thirst

• dry, warm skin

• small amounts of dark, yellow urine

• dizziness made worse when you are standing

• weakness

• cramping in the arms and legs

• crying with few or no tears

• headaches

• dry mouth with thick saliva.

Symptoms of moderate to severe dehydration include:

• low blood pressure

• fainting

• severe muscle contractions in the arms, legs, stomach, and back

• convulsions

• a bloated stomach

• heart failure

• sunken eyes with few or no tears

• lack of elasticity of the skin (when 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 doctor will review your symptoms and do a physical exam.

How is it treated?

If you are mildly dehydrated, you need to drink enough liquid to replace the fluids you have lost. Also, you need to replace the electrolytes (salts) you have lost. 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.

Nonprescription medicines are available that help replenish fluids and electrolytes. You can also replace both fluids and electrolytes by drinking sports drinks or an oral rehydration solution (ORS). Drink the solution (or give it to the dehydrated person if he or she is conscious) immediately. Do not wait until dehydration becomes severe.

Packets of oral rehydration salts are widely available. To use one of these packets, mix the contents with 1 quart or liter of drinking water. If drinking water is not available, or if you are not sure the water is drinkable, boil the water for at least 10 minutes.

If ORS packets are not available, mix 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 or honey

• 1/4 teaspoon salt

• 1/4 teaspoon baking soda (bicarbonate of soda).

Notes: If baking soda is not available, 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.

Drink sips of the ORS (or give the ORS solution to the conscious dehydrated person) every 5 minutes until urination becomes normal. (It's normal to urinate four or five 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, continue to try to drink the ORS. Your body will retain some of the fluids and salts you need even though you are vomiting. Remember to take sips of liquids slowly. Chilling the ORS may help.

If you have diarrhea, continue to drink the ORS. The fluids will not increase the diarrhea.

Someone with symptoms of severe dehydration needs to go to an emergency room or other health care facility to get intravenous fluids (fluids given directly into the veins through a needle) if possible. If able to drink, he or she should also drink the ORS.

During or after treatment of dehydration, whatever is causing the diarrhea, vomiting, or other symptoms should also be treated.

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 them rapidly.

• Know the recipe for ORS.

• If you are traveling in a country that does not have water that is safe for drinking, carry with you a quart (or liter) of boiled water and packets of ORS solution or the ingredients to make it.

What can be done to prevent dehydration?

If you have diarrhea or vomiting, or if you are not drinking very much, force yourself to begin drinking 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 five to seven times a day.

• Watch for signs of more severe dehydration and get medical help as soon as possible.