Fitness and perceived exertion in patients with fibromyalgia syndrome

OBJECTIVE: The aim of this study was to evaluate the cardiorespiratory fitness and perceived exertion of female patients with fibromyalgia syndrome (FMS) compared with that of healthy female subjects. DESIGN AND SUBJECTS: This was designed as a cross-sectional case-control study, with a consecutive sample of 30 female patients with FMS and an age-matched control group of 67 healthy female subjects. SETTING: This study was conducted at the multidisciplinary pain center of a university hospital in a city of more than 1 million inhabitants. OUTCOME MEASURES: A cardiorespiratory fitness index (PWC65%/kg) and an original perceived exertion index (B65%) were obtained from the heart rates and perceived exertions scored on a 10-point Borg scale during a submaximal cycle ergometer test. Average indexes for the FMS patients and control subjects were compared. RESULTS: The mean cardiorespiratory fitness index of the FMS patients was not significantly different from that of the controls. The mean perceived exertion index in the FMS patients was significantly greater than that of the controls, meaning that the FMS patients systematically reported higher ratings of perceived exertion during exercise. CONCLUSIONS: Cardiorespiratory fitness, as expressed by a submaximal work capacity index, seems normal in female patients with FMS compared with age- and sex-matched healthy individuals. The fact that FMS patients overscore their perception of exertion may be due to a greater overlap of peripheral pain and perceived exertion perceptions during exercise. This observation should be noted when using perceived exertion scores to prescribe and monitor exercise in FMS patients.