Fibromyalgia is typically characterized by widespread pain and is present in around 0.5-10% of worldwide population with a seven times higher presence among females than males.

Apart from pain there are symptoms of fatigue, sleep disorders, stiffness, headaches, irritable bowel syndrome, memory or concentration problems etc.

Fatigue is recognized as a part of the syndrome of symptoms that affect fibromyalgia patients.

Chronic fatigue syndrome and fibromyalgia

Earlier fatigue was classified into Chronic fatigue syndrome that was considered an associated with distinctly different entity from fibromyalgia.

According to the 2010 American College of Rheumatology (ACR) criteria for diagnosis of fibromyalgia, fatigue forms an important symptom of fibromyalgia.

Why does fatigue occur in fibromyalgia patients?

It is unknown why fatigue occurs in fibromyalgia patients. There is evidence that fatigue is the second most important parameter to measure after pain in fibromyalgia patients.

The patient with fibromyalgia often complains of feeling, “tired”, “fatigue”, “no energy”, and feeling “exhausted” or “worn out”.

Studies have shown that fatigue is more severe, constant or persistent and unpredictable than normal tiredness among fibromyalgia patients.

What symptoms do patients report?

Patients often report:-

• an overwhelming feeling of tiredness
• the tiredness is not relieved by resting or sleeping
• the tiredness is disproportional to the energy spent or stress
• the tiredness is associated with a feeling of weakness and/or heaviness
• there is distinct lack of motivation
• there is difficulty in performing daily activities
• daily tasks may be prolonged unnecessarily
• there may be difficulty in concentration, memory and thinking clearly associated with the tiredness

Fatigue measures and patient perception

Pain measurement of fibromyalgia relies on patient report and his or her perception of severity and intensity. Fatigue too depends on the patient perception.

Existing fatigue measures include Multidimensional Fatigue Inventory (MFI) and the Multidimensional Assessment of Fatigue (MAF). These have been used extensively in clinical trials on fibromyalgia.