Efficacy and Methodology of Remote Heart Rate Variability Biofeedback Interventions for Mental Health: A Systematic Review and Meta-Analysis.

Heart rate variability biofeedback (HRV-B) is a technique that has been shown to have benefits for both physical and mental health conditions. The aim of the present systematic review and meta-analysis is to describe the methodological approach and examine the efficacy of remote HRV-B interventions for mental health symptoms, including depression, stress, anxiety, and sleep as well as heart rate variability (HRV), a measure of autonomic function. A systematic literature search was conducted from five databases and eighteen studies with a total of 1352 subjects from different populations were included in this systematic review and meta-analysis based on the inclusion criteria. Meta-analysis showed a medium effect size of HRV-B for improving both depression (g = - 0.41 [- 0.049, - 0.772], p = 0.026, I2 = 72.623%, k = 10) and HRV (g = 0.443, [0.718, 0.167], p = 0.002, I2 = 56.81%, k = 10) compared to control conditions. These results remained significant after sensitivity analyses excluding high-risk, non-randomized, and outlier studies. Effect for stress was not significant (p = 0.152, k = 8). Meta-regressions identified study and protocol characteristics as significant moderators of the effect on HRV, stress, and anxiety. Specifically, maximizing resonance, screen on the device, less lab visits, less than twenty minutes of practice time per day, and female gender were beneficial for the intervention effectiveness. Overall, this study indicates that HRV-B is an effective intervention for decreasing depressive symptoms and increasing HRV across populations, and some intervention variables may influence the intervention outcomes.