Perceived and measured levels of exertion of patients with chronic back pain exercising in a hydrotherapy pool

Objective: To investigate the efficacy of using ratings of perceived exertion (RPEs) to regulate exercise intensity for patients with chronic back pain while they undergo hydrotherapy. Design: Experimental study. Setting: Hydrotherapy pool in the United Kingdom. Participants: Twenty-six patients (16 women, 10 men) with chronic low back pain of more than 12 months in duration. All were referred for hydrotherapy after attending a back pain triage clinic. Interventions: Not applicable. Main Outcome Measures: Borg Ratings of Perceived Exertion Scale; heart rate expressed as a percentage of age-predicted maximum heart rate, computed from readings using heart rate monitors; Oswestry Disability Questionnaire; and pain score from a visual analog scale. Results: At workloads below 55% of age-predicted maximum heart rate, great variability was found in the relation between RPE and exercise intensity. However, for workloads between 55% and 85% of age-predicted maximum heart rate, RPE had a strong correlation with relative exercise intensity during hydrotherapy. Conclusions: At workloads sufficient to induce an aerobic training response, and yet be safe for patients with chronic back pain. RPE was an accurate predictor of exercise intensity. At lower intensities, back and leg pain may exert a mediating influence. Further investigation is needed to determine the exact relation between back pain, exercise type, and RPE at low exercise intensities.