Ratings of perceived exertion during aerobic exercise in multiple sclerosis.

Objective: To compare ratings of perceived exertion (RPEs) during aerobic exercise in people with multiple sclerosis (MS) and control participants.

Design: Prospective experimental study.

Setting: An exercise testing laboratory.

Participants: Sedentary adults (n=12) with mild MS (Expanded Disability Status Scale score < or = 3) aged 30 to 45 years and sedentary age-matched and sex-matched controls (n=12).

Interventions: All participants underwent a graded aerobic exercise test on a cycle ergometer with breath-by-breath gas measurements and continuous heart rate monitoring.

Main Outcome Measures: After completing the Modified Fatigue Impact Scale, participants rated their effort sense every 30 seconds during exercise using the modified Borg 10-point scale.

Results: The 2 study groups showed similar baseline characteristics except for higher fatigue scores in the MS group. There were no significant differences for any fitness measure, including oxygen cost slope (in VO(2) x min(-1) x W(-1)), VO(2), or work rate during exercise. Neither heart rate nor RPE--measured at 25%, 50%, 75%, and 100% of VO(2)peak--differed between groups.

Conclusions: Despite greater reported fatigue levels, participants with MS showed similar RPE and physiologic responses to submaximal and maximal exercise compared with controls. In MS, the Borg 10-point scale may help improve evidence-based exercise prescriptions, which otherwise may be limited by fatigue, motor impairment, heat sensitivity, or autonomic dysfunction.