HRV & Mental Health

Methods

13,217 person-years of follow-up on 4,170 participants with sleep HRV monitoring

Key Findings

• Unusually high and erratic HRV predicted later stroke development
• Persistently low HRV was common in those who later developed depression
• HRV patterns changed years before clinical diagnosis
• Sleep HRV provides unique predictive value beyond waking measures

Limitations

Observational study, specific thresholds not yet established

Methods

Comparison of HRV responses to affective touch and pictures in autistic vs neurotypical children

Key Findings

• Affective touch produced greater HRV response in autistic children
• Visual emotional stimuli modulated HRV more in neurotypical peers
• Age correlated with HRV in autistic children (not cognition)
• Emotion knowledge/regulation associated with HRV in typical development
• Different modalities produce specific ANS regulation patterns

Limitations

Specific to certain types of stimuli, may not generalize

Methods

Pilot RCT of HRV biofeedback in adolescents with autism spectrum disorder

Key Findings

• HRV biofeedback is feasible in autistic adolescent population
• Participants learned to modulate HRV through biofeedback
• Improvements seen in anxiety measures
• HRV used as both intervention tool and outcome measure
• Promising as adjunct to behavioral interventions

Limitations

Pilot study with small sample, needs larger trials

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