First aid for dehydration
Learn adult first aid for someone who may have dehydration including signs, symptoms and what to do in an emergency.
What is dehydration?
Dehydration occurs when fluid and essential salts are lost from the body and not replaced. Dehydration can be the result of excess sweating during sports activities or exposure to the sun or hot humid conditions.
Signs and symptoms of dehydration
Someone with dehydration might have been sweating a lot due to hot temperatures, exertion, illness or losing fluids from vomiting and diarrhoea.
They may have:
- a dry mouth with dry or cracked lips
- a headache or be dizzy and confused
- darker urine
- less frequent urination.
Babies and young children may have pallid skin and sunken eyes. Young babies may have a sunken fontanelle (the soft spot on the top of the head). Learn heat-related first aid treatment for babies and children.
First aid steps to help someone who is dehydrated
Step 1. Get them to rest.
Reassure the person and help them to sit down.
Step 2. Give them plenty of fluids (not energy or fizzy drinks, or alcohol) to drink.
Drinking water will replace lost fluids. If you have them isotonic sports drinks will help replace salts lost through sweating.
Step 3. If their condition gets worse, seek medical advice.
More basic first aid learning for dehydration
When dehydration is not addressed, it can lead to other heat-related illnesses such as heat exhaustion and heatstroke.
Learn the symptoms and basic first aid treatment for heat exhaustion and heatstroke so you can keep yourself and others safe during hot weather.
Have our First Aid app? Open it to try the quiz and test your knowledge. If you don't have it, download the app and start learning.
Or, learn first aid treatment and symptoms for heat exhaustion and heatstroke in babies and children.
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Heatwaves UK: information and advice
Heatwaves have become more common. Understand why extreme heat is a danger and the ways you could be affected including droughts and wildfires.
Free first aid workshop for adults (ages 19+)
These free workshops do not give you a first aid qualification, but equip you with basic skills to help in a first aid emergency. Online and face-to-face sessions are available for adults and youth people (ages 10+).