Respiratory sinus arrhythmia biofeedback therapy may increase heart rate variability activity and decrease reactivity in male patients with major depressive disorder: A pilot study

Objectives: Evidence suggests that depression is associated with a decreased trend of heart rate variability (HRV), which has been considered to be associated with unfavorable physical outcomes, and not resolved using various antidepressant medication treatments despite resolution of depression symptoms. In the present study, we intended to evaluate the effectiveness of HRV in respiratory sinus arrhythmia-biofeedback therapy (RSA-BT) on depression and HRV. Methods: We recruited 67 depressed male patients who received antidepressant or benzodiazepine treatments, received a psychological assessment, and were followed with a 3-week, 6-session RSA-BT. Results: After RSA-BT, HRV reactivity showed a significant mean decrease of 6.06 in low-frequency normal unit (p = 0.001) and 0.24 in the low-frequency/high-frequency (LF/HF) ratio (p < 0.05) and borderline but nonsignificant increase of 2.63 in HF normal unit (HFnu) during the stress task compared with those data at baseline (rest), indicating parasympathetic dominance during mental stress. At resting, post-RSA-BT showed a significant increase in LF, total power, variation (VAR), LFnu, and LF/HF (p = 0.001) and a significant decrease in HFnu (p = 0.001), indicating HRV activity increase and a shift autonomic nervous balance to sympathetic side compared to pre-RSA-BT data. Those patients also showed significant reductions in depression severity post-RSA-BT (p < 0.001) after controlling medication effect. Conclusion: The study results highlight the potential rôle of RSA-BT on the increased HRV activity with a shift sympathetic predominance at rest and decreased HRV reactivity toward parasympathetic dominance during mental stress in patients with depression, which is not related to the effects of antidepressant or benzodiazepine medication.