Introduction

Dehydrationoccurs when yourbody loses more fluid than you take in.

When the normal water content of your body is reduced, itupsets the balance of minerals (salts and sugar) in your body, which affects the way it functions.

Water makes up over two-thirds of the healthy human body. It lubricates the joints and eyes, aids digestion,flushes out waste and toxins, and keeps the skin healthy.

Some of the early warning signs ofdehydration include:

• feeling Thirst and lightheaded
• a dry mouth
• tiredness
• having dark coloured, strong-smelling urine
• passing urine less often than usual

A baby may be dehydrated if they:

• have a sunken soft spot (fontanelle) on their head
• have few or no tears when they cry
• have fewer wet nappies
• are drowsy

The bodyis affectedeven when you lose a small amount of fluid.

The climate, the amount of physical exercise you are doing (particularly inhot weather)and your diet can contribute to dehydration.

You can alsobecome dehydrated as a result of an illness, such aspersistent vomiting and diarrhoea, orsweating from a fever.

These include:

• babies and infants they have a low body weight and are sensitive to even small amounts of fluid loss
• older people they may be less aware that they are becoming dehydrated and need to keep drinking fluids
• people with a long-term health condition such as diabetes or alcoholism
• athletes they can lose a large amount of body fluid through sweat when exercising for long periods

What to do

If you're dehydrated, drink plenty of fluidssuch as water, diluted squash or fruit juice. These are much more effective than large amounts of tea or coffee. Fizzy drinks may contain more sugar than you need and may be harder to take in large amounts.

If you're finding it difficult to keep water down because you're vomiting,try drinking small amounts more frequently.

Infants and small children who are dehydrated shouldn't be given large amounts of water alone as the main replacement fluid. This isbecause it can dilute the already low level of minerals in their body too much and lead to other problems.

Instead, they should be given diluted squash or a rehydration solution (available from pharmacies). You might find a teaspoon or syringe can be helpful for getting fluid into a young child.

If left untreated, severe dehydration can be serious and cause fits (seizures) , brain damage and death.

If your GP suspects dehydration, you may have a blood test or a urine test to check the balance of salts (sodium and potassium) in your body.

Contact your GP, out-of-hours service or NHS 111 straight away if you have any of the following symptoms:

• extreme thirst
• feeling unusually tired (lethargic) or confused
• not passing urine for eight hours
• rapid heartbeat
• dizziness when you stand up that doesn't go away after a few seconds

You should also contact your GP if your baby has hadsix or more episodes of diarrhoea in the past 24 hours, or if they have vomited three times or more in the past 24 hours.