Not just deep breathing.
Autonomic training.
Respirix is built on 30+ years of cardiovascular, autonomic, and clinical biofeedback research. Each protocol targets specific, measurable physiological mechanisms — not generic relaxation.
What the research shows
Four decades of peer-reviewed evidence, distilled into four protocols.
Slow breathing stimulates the vagus nerve
Breathing at 4.5–6 breaths per minute increases parasympathetic activity, reflected by higher RMSSD and HF-HRV. This shifts the nervous system from threat physiology toward safety and recovery.
Shaffer & Ginsberg, 2017; Zaccaro et al., 2018; Russo et al., 2017
Resonance breathing amplifies heart–brain coupling
At ~0.1 Hz (~5.5 breaths/min), heart rhythm oscillations synchronize with the baroreflex. This produces the largest achievable HRV waves and trains autonomic flexibility.
Lehrer et al., 2000; Vaschillo et al., 2006; Bernardi et al., 2001
HRV biofeedback retrains autonomic regulation
Real-time HRV-guided breathing improves baroreflex sensitivity, vagal-cardiac coupling, and emotional regulation capacity over weeks of consistent practice.
Goessl et al., 2017; Lehrer & Gevirtz, 2014; Thayer & Lane, 2000
Nasal diaphragmatic breathing stabilizes CO₂ sensitivity
Gentle nasal breathing improves chemoreceptor tolerance, reduces air-hunger signaling, and normalizes respiratory–autonomic feedback loops. Critical for anxiety, dysautonomia, and post-viral syndromes.
Feldman et al., 2013; Jerath et al., 2006
Physiological targets
Every protocol is designed to produce measurable changes in your autonomic nervous system.
Four evidence-based protocols
Each serves a distinct clinical role in autonomic regulation.
Resonance Frequency Breathing
Primary HRV-maximization and autonomic training
Expected effects
- Increased RMSSD and HF-HRV
- Increased HRV total power
- Improved blood pressure regulation
- Reduced sympathetic dominance
Extended-Exhale Breathing
Rapid anxiety down-regulation
Expected effects
- Increased vagal efferent output
- Reduced noradrenergic tone
- Decreased heart rate and skin conductance
Slow Diaphragmatic Nasal Breathing
Baseline autonomic stabilization
Expected effects
- Improved pulmonary stretch receptor signaling
- Improved chemoreflex stability
- Reduced baseline sympathetic tone
HRV Biofeedback Breathing
Long-term autonomic retraining
Expected effects
- Improved baroreflex sensitivity
- Increased vagal-cardiac coupling
- Sustained HRV baseline improvement
Designed for practice
Voice cues, a visual pacer, and optional real-time HRV coherence feedback. Put your phone down and let the app guide you through each protocol.
- Measurable HRV improvement, not just "relaxation"
- Direct autonomic nervous system training
- Improved baroreflex and blood pressure regulation
- Increased emotional and physiological resilience
What we measure
Clinical-grade HRV metrics tracked during every session.
Primary vagal tone marker. Root mean square of successive RR interval differences. Higher values indicate stronger parasympathetic activity.
Spectral peak power at breathing frequency (~0.1 Hz) relative to total autonomic power. Indicates how well your heart rhythm synchronizes with your breath.
Beat-to-beat heart rate from BLE chest strap. Track real-time response to each breathing phase.
Continuous monitoring of RR interval validity and packet loss ensures your HRV data is reliable and clinically meaningful.
Peer-reviewed references
The published research underpinning each protocol.
HRV & Autonomic Physiology
- Shaffer, F., & Ginsberg, J. P. (2017). An overview of heart rate variability metrics and norms. Frontiers in Public Health, 5, 258.
- Thayer, J. F., & Lane, R. D. (2000). A model of neurovisceral integration in emotion regulation and dysregulation. Journal of Affective Disorders, 61(3), 201–216.
- Thayer, J. F., et al. (2012). A meta-analysis of heart rate variability and neuroimaging studies. Neuroscience & Biobehavioral Reviews, 36(2), 747–756.
Resonance Frequency & HRV Biofeedback
- Lehrer, P. M., Vaschillo, E., & Vaschillo, B. (2000). Resonant frequency biofeedback training to increase cardiac variability. Applied Psychophysiology and Biofeedback, 25(3), 177–191.
- Vaschillo, E., Vaschillo, B., & Lehrer, P. (2006). Characteristics of resonance in heart rate variability. Applied Psychophysiology and Biofeedback, 31, 129–142.
- Lehrer, P. M., et al. (2020). Heart rate variability biofeedback improves emotional and physical health. Frontiers in Psychology, 11, 137.
Slow Breathing & Vagal Activation
- Zaccaro, A., et al. (2018). How breath-control can change your life: A systematic review. Frontiers in Human Neuroscience, 12, 353.
- Russo, M. A., Santarelli, D. M., & O'Rourke, D. (2017). The physiological effects of slow breathing in the healthy human. Breathe, 13(4), 298–309.
Baroreflex & Chemoreceptor Modulation
- Bernardi, L., et al. (2001). Slow breathing increases arterial baroreflex sensitivity. Circulation, 105(2), 143–145.
- Jerath, R., et al. (2006). Physiology of long pranayamic breathing. Medical Hypotheses, 67(3), 566–571.
- Feldman, J. L., Del Negro, C. A., & Gray, P. A. (2013). Understanding the rhythm of breathing. Nature Reviews Neuroscience, 14, 232–246.
Clinical Applications
- Goessl, V. C., Curtiss, J. E., & Hofmann, S. G. (2017). The effect of heart rate variability biofeedback training on stress and anxiety. Psychological Medicine, 47(15), 2578–2586.
- Laborde, S., Mosley, E., & Thayer, J. F. (2017). Heart rate variability and cardiac vagal tone in psychophysiological research. Frontiers in Psychology, 8, 213.
- Lehrer, P., & Gevirtz, R. (2014). Heart rate variability biofeedback: how and why does it work? Frontiers in Psychology, 5, 756.
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