You are here:


Dehydration happens when someone loses more fluid than they take in.

Young children and older people are likely to get dehydrated more easily, so it’s especially important for them to drink plenty of water.

Someone will normally get dehydrated after sweating a lot ‒ usually from exercise, being in hot conditions for a long time, or having a fever.

If you lose fluids through severe diarrhoea and vomiting, this can also cause dehydration.

If left untreated, someone with dehydration can develop heat exhaustion, which is more serious, so it’s important to make sure they rehydrate themselves as soon as possible.

Watch our video - dehydration

What to look for - dehydration

There are four key things to look for if someone is suffering from dehydration:

  1. 1 .Headaches and light headedness
  2. 2 .Dry mouth, eyes and lips
  3. 3 .Small amounts of dark urine
  4. 4. Muscle cramps

What you need to do - dehydration

Treating dehydration, next steps:

• Help them to sit down and give them plenty of water to drink.

• Giving them an oral rehydration solution to drink will help replace salt and other minerals which they’ve lost – you can buy this in sachets from any pharmacy.

• If they have any painful cramps, encourage them to rest, help them stretch and massage their muscles that hurt.

• Keep checking how they’re feeling – if they still feel unwell once they’re rehydrated then encourage them to see a doctor straight away.

Book a first aid course

With thousands of training courses across the country, be the difference between a life lost and a life saved and book now.

Find your course