Dehydration

Topic Overview

Dehydration occurs when your body loses too much fluid. This can happen when you stop drinking water or lose large amounts of fluid through diarrhea, vomiting, sweating, or exercise. Not drinking enough fluids can cause muscle cramps. You may feel faint. Usually your body can reabsorb fluid from your blood and other body tissues. But by the time you become severely dehydrated, you no longer have enough fluid in your body to get blood to your organs, and you may go into shock, which is a life-threatening condition.

Dehydration can occur in anyone of any age, but it is most dangerous for babies, small children, and older adults.

Dehydration in babies and small children

Babies and small children have an increased chance of becoming dehydrated because:

A greater portion of their bodies is made of water.
Children have a high metabolic rate, so their bodies use more water.
A child's kidneys do not conserve water as well as an adult's kidneys.
A child's natural defence system that helps fight infection (immune system) is not fully developed, which increases the chance of getting an illness that causes vomiting and diarrhea.
Children often will not drink or eat when they are not feeling well.
They depend on their caregivers to provide them with food and fluids.

Dehydration in older adults

Older adults have an increased chance of becoming dehydrated because they may:

Not drink because they do not feel as thirsty as younger people.
Have kidneys that do not work well.
Choose not to drink because of the inability to control their bladders (incontinence).
Have physical problems or a disease which makes it:
- Hard to drink or hold a glass.
- Painful to get up from a chair.
- Painful or exhausting to go to the bathroom.
- Hard to talk or communicate to someone about their symptoms.
Take medicines that increase urine output.
Not have enough money to adequately feed themselves.

Watch babies, small children, and older adults closely for the early symptoms of dehydration anytime they have illnesses that cause high fever, vomiting, or diarrhea. These are the early symptoms of dehydration:

The mouth and eyes may be drier than usual.
The person may pass less urine than usual.
The person may feel cranky, tired, or dizzy.

Check your symptoms to decide if and when you should see a doctor.

Check Your Symptoms

Do you have a concern about dehydration?

Yes

Concern about dehydration

How old are you?

Less than 3 months

3 months to 11 years

12 years or older

Are you male or female?

Male

Female

The medical assessment of symptoms is based on the body parts you have.

If you are transgender or non-binary, choose the sex that matches the body parts (such as ovaries, testes, prostate, breasts, penis, or vagina) you now have in the area where you are having symptoms.
If your symptoms aren’t related to those organs, you can choose the gender you identify with.
If you have some organs of both sexes, you may need to go through this triage tool twice (once as "male" and once as "female"). This will make sure that the tool asks the right questions for you.

Does your baby seem sick?

A sick baby probably will not be acting normally. For example, the baby may be much fussier than usual or not want to eat.

Yes

Baby seems sick

How sick do you think your baby is?

Extremely sick

Baby is very sick (limp and not responsive)

Sick

Baby is sick (sleepier than usual, not eating or drinking like usual)

Does your child have symptoms of shock?

Yes

Signs of shock

Do you have symptoms of shock?

Yes

Symptoms of shock

Do you think your baby may be dehydrated?

Yes

May be dehydrated

Are the symptoms severe, moderate, or mild?

Severe

Severe dehydration

Moderate

Moderate dehydration

Mild

Mild dehydration

Do you think your child may be dehydrated?

It can be harder to tell in a baby or young child than it is in an older child.

Yes

May be dehydrated

Are the symptoms severe, moderate, or mild?

The symptoms in a baby are different than the symptoms in an older child.

Severe

Severe dehydration

Moderate

Moderate dehydration

Mild

Mild dehydration

Is your child having trouble drinking enough to replace the fluids he or she has lost?

Little sips of fluid usually are not enough. The child needs to be able to take in and keep down plenty of fluids.

Yes

Unable to drink enough fluids

Able to drink enough fluids

Do you think you may be dehydrated?

Yes

May be dehydrated

Are the symptoms severe, moderate, or mild?

Severe

Severe dehydration

Moderate

Moderate dehydration

Mild

Mild dehydration

Are you having trouble drinking enough to replace the fluids you've lost?

Little sips of fluid usually are not enough. You need to be able to take in and keep down plenty of fluids.

Yes

Unable to maintain fluid intake

Able to maintain fluid intake

Do you think that a medicine could be causing the dehydration?

Think about whether the problem started after you began using a new medicine or a higher dose of a medicine.

Yes

Medicine may be causing dehydration

Many things can affect how your body responds to a symptom and what kind of care you may need. These include:

Your age. Babies and older adults tend to get sicker quicker.
Your overall health. If you have a condition such as diabetes, HIV, cancer, or heart disease, you may need to pay closer attention to certain symptoms and seek care sooner.
Medicines you take. Certain medicines, such as blood thinners (anticoagulants), medicines that suppress the immune system like steroids or chemotherapy, or natural health products can cause symptoms or make them worse.
Recent health events, such as surgery or injury. These kinds of events can cause symptoms afterwards or make them more serious.
Your health habits and lifestyle, such as eating and exercise habits, smoking, alcohol or drug use, sexual history, and travel.

Try Home Treatment

You have answered all the questions. Based on your answers, you may be able to take care of this problem at home.

Try home treatment to relieve the symptoms.
Call your doctor if symptoms get worse or you have any concerns (for example, if symptoms are not getting better as you would expect). You may need care sooner.

HomeTreatment

RelatedInformation

You can get dehydrated when you lose a lot of fluids because of problems like vomiting or fever.

Symptoms of dehydration can range from mild to severe. For example:

You may feel tired and edgy (mild dehydration), or you may feel weak, not alert, and not able to think clearly (severe dehydration).
You may pass less urine than usual (mild dehydration), or you may not be passing urine at all (severe dehydration).

Severe dehydration means:

Your mouth and eyes may be extremely dry.
You may pass little or no urine for 12 or more hours.
You may not feel alert or be able to think clearly.
You may be too weak or dizzy to stand.
You may pass out.

Moderate dehydration means:

You may be a lot more thirsty than usual.
Your mouth and eyes may be drier than usual.
You may pass little or no urine for 8 or more hours.
You may feel dizzy when you stand or sit up.

Mild dehydration means:

You may be more thirsty than usual.
You may pass less urine than usual.

Babies can quickly get dehydrated when they lose fluids because of problems like vomiting or fever.

Symptoms of dehydration can range from mild to severe. For example:

The baby may be fussy or cranky (mild dehydration), or the baby may be very sleepy and hard to wake up (severe dehydration).
The baby may have a little less urine than usual (mild dehydration), or the baby may not be urinating at all (severe dehydration).

Severe dehydration means:

The baby may be very sleepy and hard to wake up.
The baby may have a very dry mouth and very dry eyes (no tears).
The baby may have no wet diapers in 12 or more hours.

Moderate dehydration means:

The baby may have no wet diapers in 6 hours.
The baby may have a dry mouth and dry eyes (fewer tears than usual).

Mild dehydration means:

The baby may pass a little less urine than usual.

Shock is a life-threatening condition that may occur quickly after a sudden illness or injury.

Babies and young children often have several symptoms of shock. These include:

Passing out (losing consciousness).
Being very sleepy or hard to wake up.
Not responding when being touched or talked to.
Breathing much faster than usual.
Acting confused. The child may not know where he or she is.

Severe dehydration means:

The child's mouth and eyes may be extremely dry.
The child may pass little or no urine for 12 or more hours.
The child may not seem alert or able to think clearly.
The child may be too weak or dizzy to stand.
The child may pass out.

Moderate dehydration means:

The child may be a lot more thirsty than usual.
The child's mouth and eyes may be drier than usual.
The child may pass little or no urine for 8 or more hours.
The child may feel dizzy when he or she stands or sits up.

Mild dehydration means:

The child may be more thirsty than usual.
The child may pass less urine than usual.

A baby that is extremely sick:

May be limp and floppy like a rag doll.
May not respond at all to being held, touched, or talked to.
May be hard to wake up.

A baby that is sick (but not extremely sick):

May be sleepier than usual.
May not eat or drink as much as usual.

Shock is a life-threatening condition that may quickly occur after a sudden illness or injury.

Adults and older children often have several symptoms of shock. These include:

Passing out (losing consciousness).
Feeling very dizzy or light-headed, like you may pass out.
Feeling very weak or having trouble standing.
Not feeling alert or able to think clearly. You may be confused, restless, fearful, or unable to respond to questions.

Many prescription and non-prescription medicines can cause dehydration. A few examples are:

Antihistamines.
Blood pressure medicines.
Chemotherapy.
Diuretics.
Laxatives.

Seek Care Today

Based on your answers, you may need care soon. The problem probably will not get better without medical care.

Call your doctor today to discuss the symptoms and arrange for care.
If you cannot reach your doctor or you don't have one, seek care today.
If it is evening, watch the symptoms and seek care in the morning.
If the symptoms get worse, seek care sooner.

HomeTreatment

RelatedInformation

Call 911 Now

Based on your answers, you need emergency care.

Call 911 or other emergency services now.

Sometimes people don't want to call 911. They may think that their symptoms aren't serious or that they can just get someone else to drive them. But based on your answers, the safest and quickest way for you to get the care you need is to call 911 for medical transport to the hospital.

Seek Care Now

Based on your answers, you may need care right away. The problem is likely to get worse without medical care.

Call your doctor now to discuss the symptoms and arrange for care.
If you cannot reach your doctor or you don't have one, seek care in the next hour.
You do not need to call an ambulance unless:
- You cannot travel safely either by driving yourself or by having someone else drive you.
- You are in an area where heavy traffic or other problems may slow you down.

Home Treatment

In the early stages, you may be able to correct mild to moderate dehydration with home treatment measures. It is important to take action to prevent dehydration.

Adults and children age 12 and older

If you become mildly to moderately dehydrated while working outside or exercising:

Stop your activity and rest.
Get out of direct sunlight and lie down in a cool spot, such as in the shade or an air-conditioned area.
Prop up your feet.
Take off any extra clothes.
Drink a rehydration drink, water, juice, or sports drink to replace fluids and minerals. Drink 2 L (2 qt) of cool liquids over the next 2 to 4 hours. You should drink at least 10 glasses of liquid a day to replace lost fluids. You can make an inexpensive rehydration drink at home. But do not give this homemade drink to children younger than 12. Measure all ingredients precisely. Small variations can make the drink less effective or even harmful. Mix the following:
- 1 litre water
- ½ teaspoon table salt
- 6 teaspoons sugar

Rest and take it easy for 24 hours, and continue to drink a lot of fluids. Although you will probably start feeling better within just a few hours, it may take as long as a day and a half to completely replace the fluid that you lost.

Newborns and babies younger than 1 year of age

Don't wait until you see signs of dehydration in your baby. These signs include your baby being thirstier than usual and having less urine than usual.

If you breastfeed your baby, nurse him or her more often. Offer each breast to your baby for 1 to 2 minutes every 10 minutes.
If you use a bottle to feed your baby, increase the number of feedings to make up for lost fluids. The amount of extra fluid your baby needs depends on your baby's age and size. For example, a newborn may need as little as 1 fl oz (30 mL) at each extra feeding, while a 12-month-old baby may need as much as 3 fl oz (90 mL) at each extra feeding.
Ask your doctor if you need to use an oral rehydration solution (ORS) if your baby still isn't getting enough fluids from formula or the breast. The amount of ORS your baby needs depends on your baby's age and size. You can give the ORS in a dropper, spoon, or bottle.
If your baby has started eating cereal, you may replace lost fluids with cereal. You also may feed your baby strained bananas and mashed potatoes if your child has had these foods before.

Children ages 1 through 11

Make sure your child is drinking often. Frequent, small amounts work best.
Allow your child to drink as much fluid as he or she wants. Encourage your child to drink extra fluids or suck on flavoured ice pops, such as Popsicles. Note: Do not give your child fruit juice or soda pop. Fruit juice and soda pop contain too much sugar and not enough of the essential minerals (electrolytes) that are being lost. Diet soda pop lacks calories that your child needs.
Cereal mixed with milk or water may also be used to replace lost fluids.
If your child still is not getting enough fluids, you can try an oral rehydration solution (ORS).

Symptoms to watch for during home treatment

Call your doctor if any of the following occur during home treatment:

More serious dehydration develops.
Decreased alertness develops.
You become dizzy or light-headed, or you feel like you might faint when you rise from lying to sitting or from sitting to standing.
Decreased urination develops.
Symptoms become more severe or frequent.

Prevention

The following tips may help you prevent dehydration.

Drink plenty of water before, while, and after you are active. This is very important when it's hot out and when you do intense exercise. You can drink water or rehydration drinks.
- Drink plenty of water before, during, and after exercise.
- Take a container of water or sports drink with you when you exercise, and try to drink at least every 15 to 20 minutes.
- Use a sports drink if you will be exercising for longer than 1 hour.
Encourage your child to drink extra fluids or suck on flavoured ice pops, such as Popsicles.
Avoid high-protein diets. If you are on a high-protein diet, make sure that you drink at least 8 to 12 glasses of water each day.
Avoid alcohol, including beer and wine. They increase dehydration and make it hard to make good decisions.
Do not take salt tablets. Most people get plenty of salt in their diets. Use a sports drink if you are worried about replacing minerals lost through sweating.
Stop working outdoors or exercising if you feel dizzy, light-headed, or very tired.
Wear one layer of lightweight, light-coloured clothing when you are working or exercising outdoors. Change into dry clothing as soon as you can if your clothes get soaked with sweat. Never exercise in a rubber suit.

Prompt home treatment for diarrhea, vomiting, or fever will help prevent dehydration.

Preparing For Your Appointment

To prepare for your appointment, see the topic Making the Most of Your Appointment.

You can help your doctor diagnose and treat your condition by being prepared to answer the following questions:

When did the dehydration problem start?
What activities cause you to feel dehydrated?
Have you had a hard time getting enough fluids or holding down fluids because of vomiting, diarrhea, or fever?
If vomiting or diarrhea is causing your dehydration, how many episodes have you had in the last 24 hours? When was the last episode of vomiting or diarrhea?
Has nausea kept you from taking in enough fluids?
What prescription and non-prescription medicines do you take?
Have you been using water pills (diuretics) or laxatives?
What have you tried so far to help you rehydrate?
What activities related to sports or work make your symptoms better or worse?
Do you have any health risks?

Credits

Current as of:
July 1, 2021

Author: Healthwise Staff
Medical Review:
William H. Blahd Jr. MD, FACEP - Emergency Medicine
Kathleen Romito MD - Family Medicine
Adam Husney MD - Family Medicine
H. Michael O'Connor MD - Emergency Medicine