Dehydration
Dehydration
Dehydration happens when your body loses more fluid than it takes in. If it isn't treated, it can become serious.
You can help prevent it by drinking fluids regularly, such as water, diluted squash, or fruit juice.
Common Symptoms
⚠️ This symptom list is for educational purposes. Having these symptoms does not mean you have this condition. See a doctor for proper diagnosis.
Medicines Commonly Used
⚠️ These medicines are commonly used for confirmed diagnoses of this condition. This is NOT a recommendation or prescription. Treatment must be determined by your doctor.
No medicines have been linked to this condition yet.
When to See a Doctor
When to get medical advice
Speak to your GP practice urgently if:
- you’re extremely thirsty
- you’re feeling unusually tired (or your child seems drowsy)
- you’re confused and disorientated
- you feel dizzy when you stand up and it does not go away after a few seconds
- you have dark yellow pee or you’re peeing less than normal (or your baby has fewer wet nappies)
- you or your child are breathing quickly or has a fast heart rate
- your baby or child has few or no tears when they cry
- your baby has a soft spot on their head that sinks inwards (sunken fontanelle)
- your baby has vomited 3 times or more in the past 24 hours
- your child has had 6 or more episodes of diarrhoea in the past 24 hours
- your symptoms continue even after drinking fluids
- you think your baby or toddler is dehydrated
If your GP practice is closed, phone 111.
Causes
What causes dehydration?
Dehydration happens when you do not drink enough fluid, or when your body loses more fluid than you are taking in.
You lose fluid through sweat, vomiting, urine or diarrhoea.
Common causes of dehydration include:
- illness, for example gastroenteritis, where diarrhoea and vomiting cause you to lose a lot of fluid
- sweating too much, for example because of fever, exercise, or manual work in hot conditions
- drinking too much alcohol, since it makes you pass urine more often. A hangover headache is often a sign that you are dehydrated
- diabetes, where high blood glucose levels make you urinate more
Who is at risk of dehydration?
Anyone can become dehydrated, but some people are more at risk, including:
- babies and infants, whose low body weight makes them sensitive to even small amounts of fluid loss
- older people, who may not always notice that they are becoming dehydrated and need to drink fluids
- people with a long-term health condition, such as diabetes or alcoholism
- athletes, who can lose a large amount of body fluid through sweat during long periods of exercise
Overhydration (hyponatremia)
It is also possible to become overhydrated while exercising. Overhydration is caused by low salt levels in the blood, and can happen if you drink too much water in a short space of time.
It sometimes affects athletes when salt lost through sweat becomes diluted by drinking large amounts of water.
Symptoms of overhydration include feeling sick, vomiting and headache. In serious cases, the brain can swell, leading to confusion, seizures, coma and, rarely, death.
If you are worried that you may be overhydrated, seek medical advice.
Diagnosis
If your doctor thinks you might be dehydrated, they may ask for a blood test or a urine test to check the balance of salts in your body.
Treatment
If you're dehydrated, drink plenty of fluids such as water, diluted squash or fruit juice. These are better choices than tea, coffee or fizzy drinks.
If it's hard to keep water down because of vomiting, try drinking small amounts more often.
Oral rehydration solutions
When you're dehydrated, you lose sugar and salts, as well as water. Oral rehydration solutions can help treat this. These are powders that you mix with water and then drink. They contain a mixture of potassium and sodium salts, along with glucose or starch.
Ask your pharmacist or doctor for advice about the right rehydration solution for you or your child.
Treatment for babies
Give your baby plenty of liquids, such as breastmilk or formula. It can help to give smaller amounts of fluid more often.
Don't dilute your baby's formula (if you use it). Babies who are formula fed and those on solids can be given extra water.
Avoid giving your baby fruit juice, particularly if they have diarrhoea and vomiting, because it can make things worse.
Giving your baby regular sips (a few times an hour) of oral rehydration solution, alongside their usual feed of breastmilk, formula milk or water, will help replace lost fluids, salts and sugars. Ask your pharmacist for advice.
Treatment for infants and children
Infants and children who are dehydrated shouldn't be given only water. It can dilute the already low level of minerals in their body and make the problem worse. Instead, they should have diluted squash or oral rehydration solution. Ask your pharmacist for advice.
If your child is finding it hard to keep fluid down because of vomiting, offer small amounts more often. You may find it easier to use a spoon or a syringe to give your child small amounts of fluid in the mouth.
Treatment for severe dehydration
If severe dehydration is not treated right away, it can lead to serious complications. Severe dehydration needs hospital treatment. You will be put on a drip so fluid can be replaced in your body quickly.