What is Dehydration?
The human body is made up of 70% water. Water is essential to the normal working of the body. It lubricates joints and eyes, aids digestion, flushes out waste and toxins and keeps skin healthy.
Dehydration is when the normal water content of the body is reduced. This leads to a change in the vital balance of chemical substances in the body, especially sodium (salt) and potassium. The function of many cells depends critically on these substances being maintained at the correct levels; serious effects follow any change and dehydration can result in shock, then death.
The risk from dehydration is especially great in babies, infants and older people. It is important that they are treated urgently.
Water loss resulting from an illness such as gastroenteritis can put great strain on an infant because its body is largely made up of water. A newborn baby’s body mass is 80% water and a 12 month old infant’s body mass is 60% water. Depending on the length of the illness and how the infant responds to re-hydration therapy, there should be a successful recovery.
Symptoms of dehydration
The signs of dehydration in adults include:
- low urine output;
- concentrated, dark urine;
- dry, flushed skin;
- dry eyes;
- dry mouth (xerostomia);
- furry tongue;
- clammy hands and feet;
- sunken eyes (enophthalmos);
- dizziness; and
- confusion and irritability.
A dehydrated baby may be pale and depressed with sunken eyes. You may also notice a decrease in urine output. If the ‘soft spot’ on your baby’s head is sunken this may be an indication that it is dehydrated. This ‘soft spot’ is called the fontanel and usually closes up by the age of 12-18 months.
Chronic (long term) dehydration is bad for skin, kidneys, liver, joints and muscles and can cause cholesterol problems, headaches, reduced blood pressure (hypotension), fatigue and constipation.
Causes of dehydration
Dehydration is caused by insufficient intake of water or by losing a lot of fluid and not taking in enough to replace it.
It commonly results from an illness with persistent diarrhea and vomiting, as well as excessive sweating from a fever, heavy work in hot surroundings or heatstroke.
Dehydration can also occur as a result of drinking too much alcohol. The headache associated with a hangover indicates that your body is dehydrated. This is why it is important to drink plenty of water when you have been drinking alcohol.
If you experience any of the symptoms outlined you should make an appointment to see your GP as soon as possible. They will carry out a physical examination and may pinch the skin to see if it springs back into place immediately (turgor).
If dehydration is suspected, you may be given a blood or urine test to check the balance of sodium (salt) and potassium in your body.
Dehydration is best treated by fluid intake.
Drinking water will re-hydrate the body and isotonic drinks will replace lost salt and essential minerals.
Fluid can also be given by a naso-gastric tube (up the nose) or saline drip (infusion into a vein).
Babies, infants and elderly people need urgent treatment if they are dehydrated.
You can avoid dehydration by drinking eight large glasses of water a day and increasing your intake of water if you are ill with sickness and/or diarrhea.
When exercising, you should drink up to one liter of water per hour of exercise, on top of your normal daily amount. This should be increased if you are exercising in warm conditions, as you will dehydrate more quickly.
In hot weather, you will sweat more and lose fluid from your body. Make sure you are drinking enough water to replace lost fluids.