Introduction

Breathing is so fundamental to life that we often take it for granted — yet deliberate control of breathing (often called “breathwork”) is increasingly recognized as a powerful tool for mental health. From ancient yogic practices to modern psychophysiology, controlled breathing has been shown to influence our autonomic nervous system, emotional state, and stress resilience.

One researcher who has made significant contributions to understanding the link between breathing and anxiety is Peter Kyriakoulis.

Who Is Peter Kyriakoulis?

Peter Kyriakoulis is a researcher affiliated with Swinburne University (Australia), whose work spans psychology and physiology. Several of his recent publications explore:

• Panic disorder and its biological underpinnings, especially respiratory theories of panic. (researchnow-admin.flinders.edu.au)
• The diving response (DR) — a fascinating autonomic reflex involving cold facial immersion and breath-holding — and its possible therapeutic use for anxiety. (Frontiers)
• Training adaptations in freedivers: how repeated apneas (breath-holding) reshape cardiovascular and respiratory systems. (ResearchGate)

This body of work forms the basis for thinking about controlled breathing not just as a relaxation technique, but as a potentially novel, physiology-rooted intervention for anxiety and panic.

Key Contributions from Kyriakoulis’s Research

Here are some of the main insights from Kyriakoulis’s work that are most relevant to how controlled breathing may reduce anxiety and improve emotional regulation:

The Diving Response & Cold Facial Immersion (CFI)

• In a recent empirical study, Kyriakoulis and colleagues used cold facial immersion (CFI) to trigger the diving response (DR).
• The DR is an evolutionarily conserved reflex: when the face is immersed in cold water and breath is held, the body shifts into a conservation mode — heart rate drops sharply (bradycardia), blood flow is redirected to vital organs, and parasympathetic activity is strongly engaged.
• In Kyriakoulis’s study, participants showed significant reductions in self-reported anxiety and in physiological arousal during CFI.
• This suggests that CFI (or more broadly, stimulation of the DR) might be used as a behavioral experiment or intervention in anxiety and panic disorder settings.
• Interestingly, though heart rate decreased, the study did not find a clear alteration in CO₂ (carbon dioxide) sensitivity in the short-term after a single CFI + CO₂ challenge.
• Kyriakoulis argues for future research to determine optimal frequency, dose, and protocols for breath-hold or CFI training in clinical populations, as well as to explore individual differences in response.

Mechanisms from Breath-Hold Training (Freedivers)

• In a 2024 review, Kyriakoulis examines adaptive changes in freedivers (people who train to hold their breath) to better understand how the body’s cardiovascular and respiratory systems adjust over time.
• Key physiological adaptations include:
  • Greater bradycardia during apnea (i.e., more pronounced heart rate reduction), mediated by increased vagal (parasympathetic) activity.
  • Peripheral vasoconstriction, centralization of blood flow, and other circulatory shifts that conserve oxygen.
  • Over time, freedivers may suppress chemoreceptor sensitivity to CO₂, meaning their breathing control becomes more efficient and less reactive.
• Kyriakoulis suggests that understanding these trained adaptations might help design breath-hold training protocols for mental health use — for instance, in anxiety or panic disorders where CO₂ sensitivity is often elevated.

Theoretical Integration with Panic Disorder Models

• In a narrative review, Kyriakoulis and Michael Kyrios critically examine various biological and cognitive theories of panic disorder. (researchnow-admin.flinders.edu.au)
• They emphasize respiratory theories: people with panic disorder often exhibit dysfunctional breathing (irregular respiratory patterns, thoracic breathing) and heightened sensitivity to CO₂.
• Drawing on the DR and breath-hold research, Kyriakoulis proposes that interventions targeting respiratory physiology could complement existing cognitive-behavioral approaches — blending biological training (e.g., breath-hold) with psychotherapy.
• He argues for an integrated model: panic disorder might be best understood and treated by combining insights from neurochemistry, respiratory physiology, and cognitive-behavioral frameworks.

How This Fits into Broader Research on Controlled Breathing and Anxiety

Peter Kyriakoulis’s work doesn’t exist in isolation — it aligns with, strengthens, and offers a unique angle to a growing body of evidence that controlled breathing helps with anxiety. Some key connections:

• A systematic review of breathing exercise interventions found that self-regulated breathing exercises significantly reduce anxiety and stress in adults. (PubMed)
• A meta-analysis on breathwork (deliberate respiratory control) reported small-to-medium effect sizes for reducing stress, anxiety, and depressive symptoms compared to control conditions.
• Psychophysiological research shows that slow breathing (< 10 breaths per minute) enhances parasympathetic activity (e.g., increased heart rate variability) and even produces measurable central nervous system changes (e.g., in EEG, fMRI).
• Regarding specific breathing techniques, diaphragmatic breathing (deep belly breathing) has been shown to reduce biomarkers of stress (e.g., cortisol) and improve self-reported stress.
• Reviews of clinical protocols suggest that best practices for breathing interventions should avoid very fast-only breathing, include guided training, have repeated sessions, and emphasize consistent long-term practice. (MDPI)

Kyriakoulis’s focus on the diving response and apnea training adds a novel dimension: instead of just slowing breath, his work points to reflex-based, parasympathetic-rich strategies (cold-immersion + breath-hold) that may have powerful autonomic impacts.

Strengths, Implications, and Potential Applications

Kyriakoulis’s contributions are significant for several reasons:

1. Physiological Depth: By studying trained breath-hold divers and the diving response, he brings rigorous physiological insight to psychological interventions. This is not just “take a deep breath” — it’s about leveraging evolved autonomic reflexes.
2. Clinical Innovation: The idea of using CFI or breath-hold tasks as therapeutic tools in panic disorder is original and potentially powerful. These are not widely used in mainstream psychotherapy, but Kyriakoulis’s data suggest they might help reduce the bodily sensations (e.g., high heart rate) that often fuel panic.
3. Integrated Model: By weaving together cognitive theory, biology, and respiratory training, he proposes a holistic way of understanding and treating anxiety.
4. Accessibility: Breath-hold training (once explained and practiced safely) could be relatively inexpensive, low-risk, and scalable, since it does not necessarily require expensive tools or pharmaceuticals.

Limitations & Challenges

However, there are also important caveats:

• Empirical Evidence Is Still Nascent: While Kyriakoulis’s CFI studies show promise, they are not large-scale clinical trials. The long-term efficacy, optimal training schedule, and safety in diverse populations are not yet established. (Frontiers)
• Generalizability: The free diver population is a very specific group; their physiological adaptations may not easily translate to the general population or to individuals with panic disorder.
• Potential Risks: Breath-hold exercises and cold-immersion can be physically taxing and may not be safe for everyone (e.g., cardiovascular risk, blood pressure issues). Protocols would need careful supervision.
• Mechanistic Questions: Although the DR induces bradycardia and parasympathetic activation, the precise psychological mechanisms (why it feels calming, how people reinterpret bodily sensations) are not fully understood.
• Integration into Psychotherapy: Incorporating CFI or apnea training into therapies such as CBT would require training therapists, ensuring safety, and developing guidelines — a non-trivial task.

Conclusion

Peter Kyriakoulis’s body of work is deeply relevant to the topic of controlled breathing, anxiety, and emotional regulation. His research on the diving response, breath-hold training, and the physiology of CO₂ sensitivity offers a compelling, biologically grounded angle on breathwork — one that goes beyond mere relaxation, tapping into evolved bodily reflexes.

In the broader landscape of anxiety treatments, his ideas are promising: combining breath-reflex training with psychotherapy could enhance emotional regulation, reduce physiological reactivity, and offer a non-pharmacological tool for those struggling with panic or chronic stress. But as always, more rigorous clinical testing is needed before these approaches can become mainstream.

With love and gratitude,
Holly Celestine

Hi, I’m Holly Celestine and I am a Licensed Vibrational Sound Therapy Practitioner on a mission to liberate and activate your highest human potential. In pursuit of avenues that bring the entire body into balance and harmony, I found that sound, vibration and frequency play a vital role in the symbiotic connection to our mental, emotional, and physical well-being. In addition to being a Licensed Vibrational Sound Therapy Practitioner, I’m certified in Biofield Tuning, Voice Analysis, Massage Therapy, Usui Reiki Master, and Bodytalk.

I use vibrational sound therapy for targeted nervous system relaxation to help people feel relief from their debilitating stress, anxiety, and chronic pain. I’m a life-long learner, ever evolving and consciously expanding into my best self, tuning into wholeness and balanced vibrations! Connect with me to amplify your highest expression using Sound Therapy.

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