HRV & Mental Health

Methods

Randomized controlled trials of HRV biofeedback in PTSD patients

Key Findings

• HRV biofeedback improved RMSSD and HF power in PTSD patients
• Significant reductions in PTSD symptom severity scores
• Effects comparable to some pharmacological interventions
• Benefits maintained at 3-month follow-up
• May help restore vagal tone disrupted by trauma

Limitations

Relatively small sample sizes, varied protocols across studies

Methods

Meta-analysis of studies examining ACEs and adult HRV

Key Findings

• Childhood trauma associated with 10-20% lower adult RMSSD
• Dose-response relationship: more trauma = lower HRV
• Effects persisted after controlling for current stress
• Reduced vagal tone may mediate trauma-health connection
• Some evidence that therapy can improve HRV over time

Limitations

Retrospective trauma assessment, varied definitions of trauma

Methods

Meta-analysis of 50+ studies on depression and HRV

Key Findings

• Depressed individuals show significantly lower RMSSD and HF power
• Effect size moderate (Cohen's d ≈ 0.4-0.5)
• Bidirectional relationship: each predicts the other
• Antidepressant treatment often improves HRV
• HRV biofeedback shows medium effect size for depression

Limitations

Heterogeneous populations and depression measures

Methods

Meta-analysis of 36 articles, 2086 patients, 2294 controls

Key Findings

• Anxiety disorders show lower HF-HRV (g = -0.29)
• Time domain HRV also reduced (g = -0.45)
• Panic disorder, GAD, PTSD, social anxiety all affected
• OCD did not show significant HRV reduction
• Effects independent of medication and comorbidities

Limitations

Heterogeneous anxiety presentations and measures

Methods

Bayesian analysis of HRV changes during bipolar episodes

Key Findings

• HRV reduced during both manic and depressive episodes
• 95% probability of positive HRV change during recovery
• HRV may help monitor episode course clinically
• Pattern similar across mania and depression
• Autonomic dysfunction integral to bipolar pathology

Limitations

Sample size limits precision of effect estimates

Methods

Meta-analysis of HRV biofeedback for anxiety

Key Findings

• HRV biofeedback improves both HRV and anxiety symptoms
• CBT also improves HRV in panic disorder
• Effects seen across various anxiety presentations
• Can complement other evidence-based treatments
• Self-guided protocols show promise

Limitations

Optimal protocols still being refined