Rheumatoid arthritis (RA) is a chronic inflammatory disease that affects the synovial tissue surrounding the joints. This inflammation is associated with swelling and pain. As the disease progresses, joint tissue may become permanently damaged. The combined effects of inflammation and joint damage result in progressive disability. The causes of RA are, as yet, unknown but it is generally considered an autoimmune disease, although there is no clear evidence of what factors trigger this destructive response of the body's immune system. The onset of symptoms is gradual and insidious in most instances, although a small proportion of individuals (10–15%) may have a more rapid progression.

Joint pain, swelling and stiffness are the main symptoms of the disease, but individuals also report fatigue and general malaise. Individuals with RA describe their pain as throbbing and burning, but not as scalding, drilling or cutting (Wagstaff et al., 1985). They describe their pain differently from individuals with osteoarthritis; in particular they are likely to refer to ‘heat’ (see ‘Osteoarthritis’). Stiffness has always been harder to define and may be difficult for patients to distinguish from pain, but individuals with RA refer to resistance to movement, limited range and lack of movement (Helliwell & Wright, 1991). Clinically important levels of fatigue have been reported in over 40% of patients (Wolfe et al., 1996). A multidimensional assessment of fatigue in RA found higher levels of general and physical fatigue as opposed to mental fatigue and different aspects of fatigue selectively explained variance in different dimensions of quality of life (Rupp et al., 2004).