Why Slower Breathing Calms Your Nervous System and Strengthens Your Health
Slower breathing (≈5–6 breaths/min) increases vagal activity and improves autonomic balance. Controlled studies show decreases in stress markers (incl. cortisol), heart rate and blood pressure, and consistent increases in heart rate variability (HRV). Neuro-imaging indicates favourable shifts in networks for attention and emotion regulation. The approach is low-threshold, safe for most healthy adults, and clinically relevant for stress regulation and (pre)hypertension.[1–6]
Why breathing rate matters
The vagus nerve is the core nerve of the parasympathetic “rest-and-digest” system. Slowing and lengthening the exhale increases vagal afferent input and strengthens baroreflex mechanisms. Typical responses include lower heart rate, reduced blood pressure, and subjectively experienced calm and grounding.[2,4–6]
What controlled studies show
1) Stress, anxiety and cortisol
Randomised/controlled studies report less negative affect, improved attention and lower cortisol values after slow-paced breathing interventions.[1]
2) HRV and autonomic balance
Breathing around the resonance frequency (~0.1 Hz; ±6 breaths/min) increases HRV indices and restores sympatho-vagal balance. Systematic reviews/meta-analyses confirm effect and mechanism.[2,5]
3) Blood pressure and cardiovascular health
Meta-analyses and scoping reviews report significant reductions in systolic/diastolic blood pressure and heart rate in (pre)hypertensive populations — clinically relevant as a non-pharmacological intervention.[3,6]
4) Neural correlates of calm and focus
EEG/fMRI overviews describe shifts consistent with emotion regulation and attention (e.g., ↑alpha activity); this corresponds with reports of calm and sharper focus.[4]
From theory to practice (evidence-informed)
- Resonance breathing (~6/min): inhale 4 counts, exhale 6; start 2–5 min, 1–2×/day; extend only while comfortable.[2,5]
- Box Breathing (4-4-4-4): equal inhale/hold/exhale/hold phases; useful for acute stress regulation.[4]
- Heart-coherence training: structured practice around 5–6/min, optionally with biofeedback; robust evidence base.[2,5]
Practical aid. A simple device that slows the exhale (e.g., a breathing necklace) can make counting/apps unnecessary and increase adherence.[2]
Safety
Generally safe for healthy adults; build up gradually and stop if dizzy/short of breath. For respiratory, cardiovascular or psychiatric conditions, coordinate with a clinician.[3,6]
Conclusion
Slower breathing is a well-supported, accessible intervention that reduces stress, improves HRV, can lower blood pressure and beneficially influences neural systems for attention/emotion regulation. Physiological plausibility plus replicated effects make it a sensible choice for daily use.[1–6]
References (peer-reviewed)
- Ma X, et al. Diaphragmatic breathing reduces negative affect and cortisol while improving attention. Frontiers in Psychology. 2017. frontiersin.org
- Lehrer PM, et al. Heart Rate Variability Biofeedback: Mechanisms and Efficacy (systematic review & meta-analysis). Applied Psychophysiology & Biofeedback. 2020. springer.com
- Garg P, et al. Effect of breathing exercises on blood pressure and heart rate: systematic review & meta-analysis. 2023. pmc.ncbi.nlm.nih.gov
- Zaccaro A, et al. Psycho-physiological correlates of slow breathing: a systematic review. Frontiers in Human Neuroscience. 2018. frontiersin.org
- Lalanza JF, et al. Methods for Heart Rate Variability Biofeedback (HRVB): overview & guidelines. Applied Psychophysiology & Biofeedback. 2023. pmc.ncbi.nlm.nih.gov
- Herawati I, et al. Slow breathing as non-pharmacological therapy for hypertension: scoping review. Frontiers in Physiology. 2023. frontiersin.org
Further reading: Respira breathing necklace • Main blog: my experience with Respira • The fascinating science of conscious breathing • Breathing techniques compared • From Buddha to modern science • Breathing at work • Breathing for parents • Digital detox through breathing • Winter stress & breathing