Fatigue occurs with many illnesses and sometimes persists after the illness has resolved. Fatigue may also be the result of leading a very busy and stressful life. Chronic Fatigue Syndrome (CFS) may also be known as Myalgic Encephalitis (ME) but controversy has surrounded the terminology used to describe the syndrome in which fatigue is the main symptom. The fatigue is persistent and often overwhelming and is associated with other symptoms, such as aching muscles and tender joints, generalized weakness, headaches, sore throats and deterioration in short-term memory and concentration span. Sleep is mostly unrefreshing, and there may be increased sensitivity to noise and light. Some health professionals regard CFS as the most appropriate description of this illness because of the chronic (persistent) fatigue and the ‘syndrome’ of symptoms involving many of the body systems in the diagnosis. The Chief Medical Officer in a report on the illness in 2002 suggested that the acceptable term should be CFS/ME.
No single cause has been found for CFS/ME. There is increasing evidence, however, implicating certain factors in triggering the illness.
- Many people can identify an infection, such as an unusually severe bout of flu, or glandular fever, from which it has taken them a long time to recover, and after which they experience prolonged and persistent fatigue. Whilst it is important to rest after an acute infection, research suggests that too much rest may result in more severe symptoms in the long term.
- Life events, such as bereavements, termination of a relationship, marriage and pregnancy or change of employment, may all contribute to stress, which in turn may increase the likelihood of developing CFS/ME.
- Stress may also cause alterations in the immune system thus increasing the possibility of infections. People who lead busy and stressful lives may not give themselves enough time to recover from infections and, in returning early to their previous level of activity, make themselves more susceptible to developing CFS/ME. "Burn-out" – i.e. overworking for long periods of time, and over-training, are known to be pre-disposing factors for developing CFS/ME.
- In some people, it may be a mixture of the above whilst in others an identifiable trigger factor is not found.
Once CFS/ME has developed, there are also factors that may maintain the fatigue. For example:
- People with CFS are often physically deconditioned and complain of muscle weakness as a result of having to rest for long periods in order to feel a bit better. It is known that we may lose up to 10% of muscle power from one week of bed rest. When the body is deconditioned, various systems within the body work less well. For example, sleep pattern may be disturbed, or there may be changes in blood pressure, leading to dizziness and headaches. By resting more, this situation is perpetuated.
- When they are feeling better, people with CFS/ME may go through periods of excessive activity, which may result in a relapse. This is the so-called "boom and bust" pattern of activity.
- Weight changes, due to dietary changes and/or decreased physical activity, may alter stamina levels, making it hard to maintain previous levels of activity.
- Once the sleep pattern has been disturbed, it may be difficult to feel refreshed, so those suffering from CFS/ME may compensate by sleeping during the day making it more difficult to address the disturbed sleep pattern at night.
- Many people with CFS/ME have changes in their mood. In some people this may have preceded the fatigue; for others, this might begin after the fatigue has become debilitating. Anxiety and depression are the most common mood disorders and may themselves affect sleep patterns. This in turn may cause sensitivity to noise and light, or result in so-called "brain fog". Anxiety and depression can also affect energy levels, motivation and confidence.
- Having CFS/ME may impact on your work, social activities and personal life, which may sometimes lead to frustration, a sense of being isolated or feeling misunderstood. This might aggravate pre-existing anxiety or depression, and may also increase the pressure to recover by inappropriate activity. This perpetuates the cycle of 'booming and busting'.
Many people with CFS/ME may know all of this and may feel they are already doing everything possible to recover, but nevertheless have difficulty making progress. This in turn may lead to further feelings of frustration, anxiety and even depression.
We do not know the cause of CFS/ME and so we cannot treat the cause, but it is possible to address some of the factors maintaining fatigue, and reduce the impact of symptoms on everyday functioning. At the Royal Free London NHS Foundation Trust, the fatigue service provides a multi-disciplinary programme. Please use the link treatment options on the right to read more about treatment.