Dehydration

Dehydration occurs when your body loses more fluid than you take in.

When the normal water content of your body is reduced, it upsets 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 of dehydration include:

feeling thirsty 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 body is affected even when you lose a small amount of fluid.

Read more about the symptoms of dehydration

Symptoms

Dehydration can be mild, moderate or severe, depending on how much of your body weight is lost through fluids.

Two early signs of dehydration are thirst and dark-coloured urine. This is the body’s way of trying to increase water intake and decrease water loss.

Other symptoms may include:

dizziness or light-headedness headache  tiredness dry mouth, lips and eyes passing small amounts of urine infrequently (less than three or four times a day)

Dehydration can also lead to a loss of strength and stamina. It’s a main cause of heat exhaustion.

You should be able to reverse dehydration at this stage by drinking more fluids.

If dehydration is ongoing (chronic), it can affect your kidney function and increase the risk of kidney stones. It can also lead to muscle damage and constipation.