Validity and responsiveness of the 6 minute walk test for people with fibromyalgia

Objective. To determine the concurrent validity and responsiveness of the 6 minute walk test (6-MWT) as a measure of cardiorespiratory fitness in peop le with fibromyalgia. Methods. Subjects completed the 6-MWT, a Fibromyalgia Impact Questionnaire (FIQ), and a peak oxygen consumption (pVO(2)) exercise test before (n = 28) and after (n = 20) a 12 week exercise program. Results. The correlations between 6-MWT distance and pVO(2) before (r = 0.3 28) and after (r = 0.420) the exercise program were not significant. Signif icant correlations were obtained between 6-MWT distance and FIQ total (r = -0.494, p < 0.01) and physical impairment (r = -0.403. p < 0.05) scores. Fi fteen of 28 subjects completed the exercise program, with significant (p < 0.05) changes in 6-MWT distance (+78 m), pVO(2) (+1.8 ml/kg/min). and FIQ t otal score (-9.9). The change in 6-MWT distance was correlated significantl y (p < 0.05) with change in FIQ total score but no change in pVO(2). Conclusion. The 6-MWT was not a valid predictor of cardiorespiratory fitnes s. However, it was sensitive to change and was also significantly related t o FIQ total score.