Pain and fatigue induced by exercise in fibromyalgia patients and sedentary healthy subjects

Abstract

Objective: To examine whether general feelings of fatigue, exercise-induced pain in the extremities, and exertion were different in female patients with fibromyalgia syndrome (FS) compared with sedentary healthy women.

Methods: Thirty-seven FS patients and 20 healthy subjects were studied. Cardiovascular fitness was assessed by Aastrand's indirect, submaximal method. The period of repetitive dynamic muscle contractions and sustained static muscle contraction were measured. General feelings of fatigue before exercise and exercise-induced extremity pain were assessed by visual analogue scales. Exercise-induced exertion was recorded by Borg's Rating Scale of Perceived Exertion.

Results: No significant group difference in cardiovascular fitness was found (p = 0.8). In the FS patients general fatigue was (median 95% confidence interval) 69 (59 - 75) versus 32 (22 - 47) for the healthy controls (p < 0.0001). At the moment of interrupting the bicycle test, the perceived exertion score was 17 (16 - 18) among patients versus 13 (13 - 15) among controls (p < 0.0001). Compared with the controls, high exercise-induced extremity pain was found after sustained static and repetitive dynamic muscle contractions in the FS patients (p < 0.004), and 24 hours later the patients' pain intensities had not returned to pre-exercise values (p < 0.01).

Conclusion: High general fatigue, exercise-induced extremity pain, exertion and 24 hours post-exercise extremity pain in FS patients compared with healthy controls could not be explained by any group difference in cardiovascular fitness.