Background: The possibility that daily sessions of music-guided slow breathing may reduce 24-h ambulatory blood pressure (ABP), and predictors of efficacy were explored in a randomized, placebo-controlled trial with parallel design.
Methods: Age-matched and sex-matched hypertensive patients were randomized to music-guided slow breathing exercises (4-6 breaths/min; 1: 2 ratio of inspiration: expiration duration) (Intervention; n = 29) or to control groups who were thought to relax while either listening to slow music (Control-M; n = 26) or reading a book (Control-R; n = 31). At baseline and at follow-up visits (1 week and 1, 3 and 6 months), ABP monitoring was performed.
Results: At mixed model analysis, intervention was associated with a significant reduction of 24-h (P = 0.001) and night-time (0100-0600 h) (P < 0.0001) systolic ABP. The average reduction of systolic 24-h ABP at 6 months was 4.6 mmHg [confidence limits at 95% 1.93-7.35] and 4.1 mmHg (95% confidence limits 1.59-6.67) vs. Control-M and Control-R groups, respectively, (P < 0.001 for both). Antihypertensive treatment was selected as negative predictor of BP reduction at multivariate stepwise analysis. When antihypertensive treatment was inserted as covariate in a generalized linear model, psychological subscales assessed at baseline by the Mental Health Inventory questionnaire were found to affect systolic blood pressure reduction at 6-month follow-up (general positive affect P < 0.001; emotional ties, P < 0.001; loss of behavioral control, P = 0.035). In particular, a level of general positive affect higher than the 75th percentiles was found to be significantly associated with low treatment efficacy (odds ratio 0.09; 95% confidence limits 0.01-0.93).
Conclusion: Daily sessions of voluntary music-guided slow breathing significantly reduce 24-h systolic ABP, and psychological predictors of efficacy can be identified.