Can Addressing Autonomic Hyperarousal with Heart Rate Variability Biofeedback Enhance CBT-I Outcomes in Insomnia Disorder?

Objectives: Insomnia often involves physiological hyperarousal, particularly autonomic dysregulation. Although Cognitive Behavioral Therapy for Insomnia (CBT-I) is effective, some patients do not achieve complete remission. This preliminary study evaluated whether combining CBT-I with heart rate variability (HRV) biofeedback could enhance treatment effects by improving autonomic regulation.

Methods: Forty-four adults with insomnia were randomized to either a CBT-I group or a combined group that received HRV biofeedback (HRV-BF) and CBT-I (CBT-I+BF group). Both groups received seven weekly CBT-I sessions, with HRV-BF introduced in session four in the CBT-I+BF group. The primary outcome measure was the Insomnia Severity Index (ISI). Other outcome measures included the Pre-Sleep Arousal Scale (PSAS), sleep diaries, and HRV metrics. Assessments were conducted at baseline, post-treatment, and six-month follow-up. ISI and PSAS were also assessed at week 4 before the introduction of HRV-BF.

Results: Both groups significantly improved in insomnia severity, pre-sleep arousal, and some sleep diary variables.The CBT-I+BF group showed unique and significant improvement in subjective total sleep time. While overall autonomic balance only showed a trend-level improvement in the CBT-I+BF group, sensitivity analyses on participants with more severe objective sleep disturbance suggested greater autonomic balance improvement for the CBT-I+BF group.

Conclusions: Incorporating HRV-BF into CBT-I did not significantly enhance the benefits of CBT-I alone in this study. However, it offers additional advantages for individuals with more objective sleep disturbance, particularly in improving autonomic balance. Future research should identify optimal treatment intensity and explore the utility of HRV-BF in various insomnia sub-populations.