Physiological and perceptual effects of self-selected and classical relaxing music on resting metabolic rate: a crossover trial

BACKGROUND: A common recommendation for assessing resting metabolic rate (RMR) is that measurements be undertaken while avoiding activities like reading and listening to music. Listening to music, however, is sometimes used to reduce boredom or keep subjects awake, although it remains unclear whether music significantly alters RMR. METHODS: This randomized crossover trial enrolled 32 subjects and examined the impact of relaxing music during RMR tests. Indirect calorimetry was used to quantify RMR, oxygen consumption, carbon dioxide production (VCO2), ventilation (V-E), respiratory rate, and respiratory exchange ratio (RER); the Karolinska Sleepiness Scale (KSS) and boredom-excitement scale (BES) assessed perceptual responses. Subjects were randomized to three 15-minute conditions in a counter-balanced order: control (no music), classical relaxing music, and self-selected relaxing music. RESULTS: There was no significant effect of music on RMR (ANOVA, F[2,60] = 2.4, P=0.10). The difference in RMR between control and classical conditions was 9 kilocalories (95% confidence interval [CI], -33 to 51), while the difference between control and self-selected conditions was 34 kilocalories (95% CI: -5 to 73). Compared to control, both music conditions caused small, statistically significant increases in most cardiorespiratory parameters (VCO2, V-E, respiratory rate, RER, heart rate) and reduced boredom on BES. No effects on the KSS were found. V-E and BES ratings were slightly higher with self-selected music than classical music. CONCLUSIONS: Listening to relaxing music elicits small changes in physiological and perceptual responses during RMR testing but does not likely cause clinically meaningful fluctuations in RMR.