Objectives: The aims of this study were to assess the effects of an intervention of Iyengar yoga and coherent breathing at five breaths per minute on depressive symptoms and to determine optimal intervention yoga dosing for future studies in individuals with major depressive disorder (MDD). Methods: Subjects were randomized to the high-dose group (HDG) or low-dose group (LDG) for a 12-week intervention of three or two intervention classes per week, respectively. Eligible subjects were 18-64 years old with MDD, had baseline Beck Depression Inventory-II (BDI-II) scores ≥14, and were either on no antidepressant medications or on a stable dose of antidepressants for ≥3 months. The intervention included 90-min classes plus homework. Outcome measures were BDI-II scores and intervention compliance. Results: Fifteen HDG (Mage=38.4±15.1 years) and 15 LDG (Mage=34.7±10.4 years) subjects completed the intervention. BDI-II scores at screening and compliance did not differ between groups (p=0.26). BDI-II scores declined significantly from screening (24.6±1.7) to week 12 (6.0±3.8) for the HDG (-18.6±6.6; p < 0.001), and from screening (27.7±2.1) to week 12 (10.1±7.9) in the LDG (-17.7±9.3; p < 0.001). There were no significant differences between groups, based on response (i.e., >50% decrease in BDI-II scores; p=0.65) for the HDG (13/15 subjects) and LDG (11/15 subjects) or remission (i.e., number of subjects with BDI-II scores <14; p=1.00) for the HDG (14/15 subjects) and LDG (13/15 subjects) after the 12-week intervention, although a greater number of subjects in the HDG had 12-week BDI-II scores ≤10 (p=0.04). Conclusion: During this 12-week intervention of yoga plus coherent breathing, depressive symptoms declined significantly in patients with MDD in both the HDG and LDG. Both groups showed comparable compliance and clinical improvements, with more subjects in the HDG exhibiting BDI-II scores ≤10 at week 12.
Keywords: Iyengar; breathing; depression; dosing; randomized; yoga.