Effect of distractive auditory stimuli on exercise tolerance in patients with COPD.
We tested the hypothesis that a distractive stimulus, such as music, introduced during exercise can reduce perception of respiratory effort at any given level of exercise, whereas sensory deprivation increases effort perception. Thirty-six patients with moderate COPD participated in four sessions of symptom-limited exercise. The first session familiarized the subject with the protocol. The other sessions were performed under partial visual isolation while listening to music (M), or to grey noise (GN), or in silence (SIL), presented in randomized order. Subjects graded their respiratory effort using the Borg rating of perceived exertion (RPE) scale. Total exercise time (EXT) and external work (WT) were objective indices of exercise tolerance. EXT was 22% longer with M than with either GN or SIL (p < 0.001), and WT was 44% and 53% greater with M than with GN or SIL, respectively (p < 0.001). These increases occurred at a heart rate that was only a few beats higher than during GN or SIL (104 +/- 3 bpm for M and 101 +/- 3 bpm for GN and SIL), a minimal difference that was statistically significant (p < 0.001). At every level of exercise, perceived exertion with M was lower than for either GN or SIL (p < 0.001). Although the respective RPE was higher for SIL than for GN (p < 0.01) at every level of exercise, WT and EXT were no different. These data indicate that perceived effort can be significantly influenced by external factors. This in turn suggests that the use of distractive stimuli during exercise training programs with patients with COPD may significantly decrease perceived symptoms of respiratory discomfort, thus allowing the patient to exercise to a higher intensity, and potentially achieving more effective exercise reconditioning training.