Blood Pressure and Autonomic Changes From 12-Weeks of Yoga-Based Slow Breathing Exercises

Background Slow breathing exercises have been shown to reduce blood pressure and sympathetic tone acutely, though long-term effects are not well documented. Objective Assess changes in blood pressure and autonomic measures from before and after 12 weeks of yoga-based slow breathing. Methods We conducted a secondary analysis to assess changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), and autonomic tone as measured by spectral analysis of heart rate variability after 12 weeks of yoga-based slow breathing among 99 healthy participants. Participants were randomized to 2 different slow breathing techniques, length of inhale = exhale (I = E) vs length of inhale<exhale (E>I), to examine if breath ratio produced differential effects. Results The baseline average SBP and DBP was 105 ± 11 and 67 ± 8 mmHg respectively. Among the 11 participants with elevated blood pressure, SBP/DBP was 126 ± 11.0/80 ± 5 mmHg. SBP and DBP decreased significantly (−2.4 ± 7.3 and −1.6 ± 5.5 mmHg, respectively) at 12 weeks among all participants. Blood pressure among slow breathing participants with elevated baseline SBP >120 mmHg and/or DBP >80 mmHg reduced further (−10.3 ± 7.9 and −3.8 ± 5.5 mmHg, respectively). In our regression model, baseline SBP was associated with further decreases in SBP from baseline to 12 weeks. There were no significant differences in BP changes by breath ratio group. No significant changes were observed from baseline to 12 weeks in autonomic tone as measured with spectral analyses. Nor were there any observed correlations between changes in blood pressure and autonomic tone. Conclusion 12-weeks of slow breathing exercises were associated with clinically significant reduction of blood pressure in the absence of statistically significant changes in autonomic tone as measured by heart rate variability. Further research is warranted regarding the mechanisms and clinical efficacy of slow breathing on blood pressure regulation.