Fatigue
Reviewed by Dr Stuart Crisp, specialist registrar and Dr John Pillinger, GP
Fatigue as a concept is extremely hard to define, since everybody has their own idea of what being tired means. Everybody is tired once in a while - the most common reason is, of course, lack of sleep.
Fatigue can also be caused by a wide range of illnesses and diseases. In such cases, a person usually finds they suddenly (or even gradually) need more rest and sleep. This may affect their performance at work.
Fatigue is also common when you are feeling down.
How much sleep do you need?
The need for sleep can vary quite a lot between individuals, although it is usual to require less sleep as you get older.
Children
Small children often need a lot of sleep. Toddlers, for example, may need between 14 and 16 hours a day.
The need for sleep slowly declines through childhood. Most schoolchildren will need at least 10 to 12 hours of sleep to be at their best during the day.
It does not help children if they are allowed to stay up late and are then hauled out of bed the next morning.
Adults
Most adults need six to eight hours of sleep, but this can differ from one person to another.
A good night's sleep seems to help concentration and improve the immune system, minimising the risk of illness.
What causes fatigue?
There are a number of conditions that cause fatigue - some of the most common are listed below.
Anaemia
Anaemia due to a lack of iron is most often seen in women who have prolonged or heavy periods. Blood is lost every month, which means more iron is needed in the diet.
Other conditions that can give rise to anaemia include:
In times of rapid growth in children, iron deficiency anaemia can be caused by certain small-intestinal diseases or syndromes, which lower the amount of nutrition the body is able to absorb, such as gluten-intolerance or Crohn's disease.
Infections
It is quite normal for fatigue to be brought on by various infections. After a bout of flu, for instance, you can feel tired for a couple of weeks.
Sometimes you may only notice a disease or illness because you have fatigue. This can be true of glandular fever, Lyme disease and AIDS.
Causes of fatigue
- Lack of sleep.
- Iron deficiency anaemia.
- Infections such as flu.
- Depression.
- Cancer.
- Low metabolism.
- High metabolism.
- Diabetes.
- Chronic fatigue syndrome (CFS).
Depression
You can easily become tired if you are depressed or experiencing emotional stress. Depression that requires medical help often shows itself through heavy fatigue.
A specific tendency towards fatigue during the winter can be a sign of winter depression (known as seasonal affective disorder), which nowadays can be treated successfully.
Cancers
Most forms of cancer cause fatigue to a certain degree. Therefore, it is extremely important to visit a doctor if you experience fatigue that seems to have no specific cause (eg insomnia).
Cancer can also manifest itself as lack of appetite and weight loss.
Metabolism
For people with a low metabolism rate (when the body is slow to turn food into energy), fatigue and an increased need for sleep can become extreme. If you suspect your metabolism rate is too low, you should see a doctor, because there are effective treatments available.
A high metabolism rate can also cause fatigue. In such cases, a high pulse rate makes it difficult to rest and leads to profound tiredness and a feeling of being unfit. There are also readily available treatments for this disorder.
Diabetes
Diabetes is another illness that can cause fatigue. Diabetes must be diagnosed and treated to stop it getting worse. A diagnosis can usually be made from a simple blood test.
Chronic fatigue syndrome
Chronic fatigue syndrome is a condition that causes exhaustion and fatigue without explanation.
There is no hard and fast test for this syndrome, but it is diagnosed 'by exclusion'. This means that if doctors have tested for everything else without success, this is the only possibility left.
Chronic fatigue is nonetheless a real condition. Although it is not directly treatable, it can be managed well enough to allow people to return to good health in time.
Tackling fatigue
First and foremost, you need to ensure that you lead a healthy life. This means a good diet, exercise and plenty of sleep.
Vitamins and minerals are necessary for many of the body's processes, and a healthy diet ensures your body can function at its best.
It may sound strange, but lack of exercise can increase feelings of fatigue. If you're not used to doing exercise, long walks are a good way to start. Exercise that involves all the major muscle groups is recommended, eg swimming.
What should I do if the fatigue continues?
Try to ascertain whether the fatigue is simply due to prolonged lack of sleep. If this can be excluded, and the fatigue has gone on for three to four weeks, it might be a good idea to see a doctor for a check-up.
This is particularly important if you are suffering from other symptoms such as:
- night sweats
- weight change
- breathlessness
- pale mucous membranes in the nose and mouth
- blood in faeces or urine
- swollen lymph glands
- thirst.
. This list is by no means complete. Fatigue is a good enough reason by itself for you to seek your doctor's advice.
© Copyright 1998 - 2009 NetDoctor.co.uk - All rights reserved 
