Science

Introduction

Over the past several years, breathwork—the deliberate, conscious manipulation of breathing patterns—has moved from the margins of alternative wellness into the spotlight of mainstream scientific inquiry. Once the province of yoga studios and psychedelic retreat centres, controlled breathing practices are now the subject of randomised controlled trials, neuroimaging studies, and meta-analyses published in top-tier journals. The question is no longer whether breathing deliberately does something to the body and mind—it clearly does—but rather what, how much, and for whom.

This article summarises findings from over twenty peer-reviewed studies spanning 2014–2026, covering a range of breathwork traditions from slow-paced coherent breathing to fast-paced conscious connected breathwork (CCB) and the Wim Hof Method. The research includes meta-analyses, randomised controlled trials, neurophysiological studies, and observational investigations. Taken together, these papers paint a picture of a field at an inflection point: promising early results, increasingly rigorous methods, and a growing understanding that what happens when you change how you breathe is far more profound—and more complex—than most people assume.

What Is Conscious Connected Breathwork?

Conscious connected breathwork is an umbrella term covering several traditions—Holotropic Breathwork (developed by Stanislav and Christina Grof), Transformational Breathwork, Rebirthing Breathwork, and others—that share a common technique: breathing continuously at a faster-than-normal rate, without pauses between inhale and exhale, for an extended period (typically 20–90 minutes).¹ This is sometimes referred to as "high ventilation breathwork" (HVB) or "circular breathwork" in the research literature.²

These practices differ significantly from slow-paced techniques like box breathing or coherent breathing, which aim to calm the nervous system by slowing the breath to around 5–6 breaths per minute. CCB does something closer to the opposite: it deliberately increases ventilation, which triggers a cascade of physiological changes including respiratory alkalosis (a rise in blood pH), decreased carbon dioxide levels, altered cerebral blood flow, and shifts in autonomic nervous system activity.¹ These physiological changes can, in turn, produce altered states of consciousness with striking similarities to those reported under the influence of psychedelic substances.³

For readers interested in a broad, accessible introduction to the history and science of breathing, journalist James Nestor's Breath: The New Science of a Lost Art remains one of the most widely cited lay treatments of the subject.⁴

The Evidence for Mental Health Benefits

Breathwork and Stress: The Meta-Analytic Picture

The most comprehensive overview of breathwork's effects on mental health comes from Fincham and colleagues' 2023 meta-analysis, published in Scientific Reports. Analysing twelve randomised controlled trials with a combined 785 participants, the researchers found that breathwork was associated with significantly lower self-reported stress compared to non-breathwork control conditions, with a small-to-medium effect size (Hedges' g = −0.35).⁵ Secondary analyses of anxiety (20 studies) and depression (18 studies) yielded similar results, with effect sizes of g = −0.32 and g = −0.40, respectively.

These are not large effects by the standards of pharmacological interventions, but they are meaningful—comparable in magnitude to the effects of exercise on depression, and achieved through a practice that requires no equipment, no medication, and relatively little time. Importantly, the authors urged caution, noting that most studies carried a moderate risk of bias, and advocating for more rigorous designs to prevent what they termed a potential "miscalibration between hype and evidence."

Conscious Connected Breathwork and Anxiety

A 2026 randomised waitlist-controlled trial by Blake, published in the Journal of Affective Disorders, provides the most direct test of CCB's effects on anxiety to date. The study randomly assigned 107 adults to either six weekly 90-minute sessions of online CCB or a waitlist control. The breathwork group showed a statistically significant reduction in anxiety, with a large within-group effect size (Cohen's d = 1.44). Participants' mean anxiety scores dropped from 43.87 to 33.31—a shift from moderate anxiety to below even the threshold for mild anxiety—within just six sessions.⁶

When compared to published benchmarks for established therapies, this effect size is notable. Meta-analytic data show that individual cognitive behavioural therapy (CBT) typically produces pre–post effect sizes around d = 1.30, while psychodynamic therapy, EMDR, and interpersonal therapy produce effects ranging from d = 0.78 to d = 1.17. Although this is not a direct head-to-head comparison, the finding suggests that CCB merits serious investigation as a complementary approach to anxiety treatment. The study also highlighted that CCB was delivered entirely online, suggesting that these benefits may not require in-person facilitation—an important consideration for scalability and accessibility.

The Stanford Breathing Study

A 2023 study led by Balban and colleagues at Stanford University, published in Cell Reports Medicine, compared three different daily 5-minute breathing exercises (cyclic sighing, box breathing, and cyclic hyperventilation with retention) against mindfulness meditation over one month. All four conditions improved mood and reduced anxiety, but breathwork—particularly cyclic sighing, which emphasises prolonged exhalations—produced greater improvements in mood and greater reductions in respiratory rate than meditation alone.⁷

This study is significant because it demonstrates that even very brief daily breathwork practices (just five minutes) can produce measurable psychological benefits, and that active control of breathing may offer advantages over passive observation of the breath, at least for mood improvement.

The Wim Hof Method and Depression

On the high-arousal end of the spectrum, two studies examined the Wim Hof Method (WHM)—a protocol combining cyclic hyperventilation, breath holds, and cold exposure. Blades and colleagues randomised 84 women with high stress and depressive symptoms to either the WHM or an active control condition involving slow breathing and warm showers over three weeks.⁸ Both groups showed substantial improvements: a 24% reduction in depressive symptoms, 27% reduction in anxiety, and 20% reduction in perceived stress, sustained at a three-month follow-up.

Critically, there was no significant difference between the two conditions on most measures, which may mean that both were genuinely effective or that the effects were partly attributable to time, attention, and expectation. The one area where the WHM did outperform the control was in reducing daily rumination about stressful events during the first two weeks of practice.

A larger 2025 semi-randomised trial by Fox, Biddell, and King (N = 404) compared the WHM (in-person and remote) to mindfulness meditation over 29 days.⁹ While minimal between-condition trait-level changes emerged, the WHM conditions showed greater momentary improvements in self-reported energy, mental clarity, and ability to handle stress immediately following daily practice. Intriguingly, the impact of the WHM increased across days, while the impact of meditation decreased—suggesting a cumulative, dose-dependent benefit that unfolds over time.

Brief Breathwork with Retention

The challenge of designing adequate controls for breathwork research was underscored by a 2024 randomised placebo-controlled trial from Fincham and colleagues. The study tested brief remote sessions of high ventilation breathwork with breath retention against a well-designed active comparator and found significant stress improvement in both groups—but no significant between-group difference.¹⁰ This finding highlights a recurring theme in the literature: breathwork consistently appears beneficial, but demonstrating that its effects exceed those of other forms of structured breathing and attention remains difficult.

How Does It Work? The Physiology of Breathing on Purpose

Slow Breathing: The Vagal Pathway

A systematic review by Zaccaro and colleagues, published in Frontiers in Human Neuroscience, synthesised the psychophysiological evidence for slow breathing techniques. The emerging model centres on the vagus nerve, the major communication highway between body and brain. Slow breathing appears to enhance vagal tone, increasing heart rate variability (HRV)—a widely accepted marker of stress resilience and emotional regulation.¹¹

At the brain level, slow breathing is associated with increased alpha-wave activity and decreased theta-wave activity on EEG, patterns associated with calm alertness and reduced anxiety. Slow breathing techniques also appear to increase blood oxygenation in the prefrontal cortex and activate brain areas involved in the regulation of internal bodily states. The researchers proposed that these effects operate through both bottom-up mechanisms (vagal stimulation conveying relaxation signals to the brain) and top-down processes (the focused attention required for breath control engaging executive networks).

Fast Breathing: The Sympathetic Activation and Altered States Pathway

CCB and other fast-paced breathwork practices work through a different, though complementary, set of mechanisms. The comprehensive review by Fincham and colleagues in Neuroscience and Biobehavioral Reviews describes how voluntary hyperventilation causes a drop in blood CO₂ levels (hypocapnia), leading to respiratory alkalosis, reduced cerebral blood flow, and increased neuronal excitability.¹ These changes are thought to produce a kind of "interoceptive prediction error"—a mismatch between what the brain expects to feel and what the body is actually experiencing—which may be a key mechanism underlying both the altered states and the therapeutic potential of these practices.

A 2025 study by Havenith and colleagues, published in Communications Psychology, provided the most detailed physiological tracking of a breathwork session to date. Comparing both Holotropic and Conscious-Connected breathwork against passive-breath controls, the researchers found that reductions in end-tidal CO₂ were significantly correlated with the onset of altered states of consciousness (r = −0.46, p < 0.001).² Both breathwork styles produced highly similar physiological and experiential outcomes, suggesting that the specific tradition matters less than the core breathing technique itself.

Perhaps most strikingly, the subjective experiences reported by breathwork participants—measured using standard psychedelic research questionnaires (the 11-DASC and MEQ-30)—resembled those produced by psychedelic substances across multiple experiential domains, including ego dissolution, mystical experience, and feelings of unity.

Neuroimaging: What Happens in the Brain

A 2025 neuroimaging study by Kartar and colleagues, published in PLOS One, extended these findings by examining cerebral blood flow during high ventilation breathwork accompanied by music.¹² The researchers found that the intensity of altered states was proportional to cardiovascular sympathetic activation. HVB produced large, global reductions in cerebral blood flow, but with a notable exception: blood flow to the right amygdala and anterior hippocampus—brain regions involved in processing emotional memories—progressively increased during the session. Meanwhile, blood flow to the left operculum and posterior insula, regions involved in representing the internal state of the body (including breathing), decreased significantly. These hemodynamic changes correlated with participants' ratings of psychedelic-like experiences, providing a neurobiological window into the subjective shifts that breathwork practitioners describe.

The EEG and Mood Evidence

Bahi and colleagues provided further neurophysiological evidence from a 2024 study measuring EEG changes before and after a single session of conscious connected breathing.³ Post-session, participants showed significant reductions in tension, confusion, and depression on the Profile of Mood States, along with increased self-esteem. On the altered states questionnaire, breathwork produced scores on the "Oceanic Boundlessness" subscales (blissful state, spiritual experience, experience of unity, insightfulness, disembodiment) that were comparable to those produced by high doses of psilocybin.

Heart Rate Variability: From Sympathetic Storm to Parasympathetic Calm

The Havenith et al. (2025) study also revealed an important dynamic pattern in heart rate variability during and after breathwork.² During the active breathing phase, HRV decreased—reflecting intense sympathetic nervous system activation and a kind of voluntary "stress rehearsal." After the session, however, parasympathetic tone increased significantly, comparable to improvements achieved with dedicated relaxation practices.

This pattern—initial sympathetic activation followed by enhanced parasympathetic recovery—fits within the framework of hormesis: the idea that controlled exposure to manageable stressors builds resilience. The same principle underlies the benefits of exercise, intermittent fasting, and cold exposure.

Breathwork and the Immune System

One of the most rigorous and widely cited studies in the breathwork literature is the 2014 randomised controlled trial by Kox and colleagues, published in the Proceedings of the National Academy of Sciences. Healthy male volunteers were trained for ten days in the Wim Hof Method (meditation, breathing exercises, and cold exposure), then injected with bacterial endotoxin to trigger an innate immune response.¹³

The results were striking. Trained participants showed significantly higher levels of epinephrine during the breathing exercises, which in turn was associated with a faster and greater rise in the anti-inflammatory cytokine IL-10. Levels of the pro-inflammatory cytokines TNF-α, IL-6, and IL-8 were significantly lower in the trained group, and flu-like symptoms were reduced.

The significance of this study was twofold. First, it demonstrated that the sympathetic nervous system and the innate immune response—both widely regarded as involuntary, automatic systems—could be deliberately influenced through relatively simple techniques learned in a short training programme. Second, it suggested potential applications for conditions involving excessive inflammation, including autoimmune diseases. A subsequent proof-of-concept trial found that the same protocol attenuated inflammation and disease activity in patients with axial spondyloarthritis, an autoimmune form of arthritis.¹⁴

Breathwork in Cancer Care

Emerging research is beginning to explore breathwork's immunomodulatory potential in oncology. A 2025 study published in Cancers examined the effects of conscious connected breathing in 93 breast cancer patients undergoing postoperative radiotherapy as part of an Integrative Breathwork Psychotherapy (IBP) programme.¹⁵ The researchers found measurable changes in cortisol and prolactin levels during CCB sessions—an early signal that breathwork may influence the hormonal and immune milieu in ways that could be relevant to cancer patients coping with the physiological burden of treatment. While the study is preliminary, it opens an intriguing avenue of inquiry at the intersection of breathwork, psychoneuroimmunology, and supportive oncology care.

Breathwork and Altered States of Consciousness

The Psychedelic Connection

Several studies have now documented that breathwork can induce altered states of consciousness with measurable similarities to psychedelic experiences. This is not merely anecdotal: the similarities have been quantified using standardised instruments developed for psychedelic research.

Uthaug and colleagues assessed 58 Czech-speaking participants before and after Holotropic Breathwork sessions.¹⁶ Despite relatively modest ratings on psychedelic experience scales (0–34% of maximum), participants showed significant improvements in non-judgement that persisted for four weeks, along with significant decreases in stress and increases in life satisfaction. Experiences of "blissful state" and "spiritual experience" were positively correlated with improvements in life satisfaction—a pattern previously observed with psilocybin, ayahuasca, and 5-MeO-DMT.

The Autonomic Nervous System as a Bridge

A 2024 study by Bonnelle and colleagues in the Journal of Psychopharmacology provides a potential mechanistic link between breathwork and psychedelic experiences.¹⁷ Investigating the autonomic nervous system's role during DMT administration, they found that "sympathovagal coactivation"—the joint engagement of both sympathetic and parasympathetic systems—was positively related to ratings of spiritual experience and insightfulness, and predicted improved well-being two weeks later.

Notably, the researchers observed that pre-injection sympathovagal balance predicted the depth of the subsequent experience—a finding with direct implications for breathwork practice. If breathing techniques can cultivate a more balanced autonomic state, they may serve as a form of preparation that enhances the depth and therapeutic value of non-ordinary states of consciousness, whether pharmacologically or non-pharmacologically induced.

Expanding Applications: Pain, Trauma, and Somatic Integration

Breathwork for Chronic Pain

A 2025 proof-of-concept study by Pratscher and colleagues examined Guided Respiration Mindfulness Therapy (GRMT)—an integrative breathwork intervention combining conscious connected breathing with somatically focused mindfulness and relaxation—for adults with chronic pain.¹⁸ While the study was designed primarily to assess feasibility and acceptability, the preliminary results showed clinical significance for pain reduction. The researchers noted that the non-ordinary states of consciousness occasioned by the breathwork component may play a role in the intervention's effects, consistent with broader findings linking altered states to therapeutic outcomes.

Movement-Informed Breathwork

In 2026, Caddye and colleagues introduced Movement-informed Breathwork (MiB), a novel approach integrating a slower form of conscious connected breathing with targeted neuromuscular contraction and relaxation cycles.¹⁹ Published in OBM Integrative and Complementary Medicine, the paper draws on torque chain theory, fascial research, and sensorimotor trauma therapy principles to create a framework that bridges traditional breathwork, movement therapy, and clinical practice. MiB is designed to be scalable from brief 5–10 minute sessions for nervous system downregulation to extended 90-minute sessions for deeper somatic exploration and trauma integration, and represents an effort to systematise the body-oriented dimension of breathwork that many practitioners describe but few studies have formalised.

Limitations and Caveats

For all the promising results, the breathwork research literature carries substantial limitations that merit honest acknowledgment.

Sample sizes and demographics. Most studies remain small, with participant pools heavily skewed toward Western, educated, white women. Blake's 2026 CCB trial, for instance, was 80% female and 79.7% white.⁶ These demographics may not reflect the broader population that could benefit from breathwork, and the findings cannot yet be considered generalisable.

Lack of blinding and active controls. It is essentially impossible to blind participants to whether they are breathing fast or slowly, making true placebo controls a significant design challenge. Several studies have used waitlist controls, which cannot account for expectation effects, attention, or the simple passage of time. The Blades et al. WHM study attempted to address this with an active control (slow breathing) but found both groups improved equally—raising the possibility that non-specific factors drove the improvements.⁸

Short follow-up periods. Most studies measure outcomes only immediately after the intervention or at relatively brief follow-up periods. Long-term durability of effects remains largely unknown. Future research should explore optimal session duration, frequency, and the sustainability of benefits.⁶

Risk of bias. The Fincham et al. meta-analysis found that most included studies were at moderate risk of bias, and the authors explicitly warned against allowing enthusiasm to outpace evidence.⁵

Safety concerns. The physiological changes induced by CCB—particularly hypocapnia and alkalosis—are not trivial. People with certain cardiac, respiratory, or psychiatric conditions may be at risk. Patrick McKeown has raised concerns that regular CCB practice could reduce CO₂ tolerance over time, though evidence on this point remains limited.⁶ Fincham and colleagues emphasise the importance of proper screening, trained facilitation, and informed consent.¹

The "experience" variable. While several studies link the depth of altered states to subsequent well-being improvements, the Havenith et al. (2025) study found that post-session biomarker changes (immune and stress markers) were predicted not by the degree of CO₂ reduction but by the depth of subjective experience—suggesting that the psychological content of the experience, rather than the raw physiological perturbation, may be the more important therapeutic ingredient.² This is an important finding, but it also makes the mechanisms harder to control and standardise.

Future Directions

The research collectively points toward several promising avenues. Direct comparisons between CCB and established therapies (such as CBT) would provide the clearest evidence of breathwork's relative efficacy. Head-to-head trials with well-matched active controls are the field's most pressing need.

Studies in diverse populations—different ages, ethnicities, socioeconomic backgrounds, and clinical presentations—are essential for understanding who benefits most and whether CCB is safe and effective outside the demographic groups studied so far.

Mechanistic research, particularly neuroimaging studies tracking brain activity during and after CCB sessions, will help clarify whether the therapeutic effects arise primarily from the physiological perturbation, the altered state of consciousness, the emotional processing, or some combination of these. The Kartar et al. neuroimaging study represents an important step in this direction.¹²

Longitudinal studies comparing different session lengths, frequencies, and delivery formats (online vs. in-person, individual vs. group) will be necessary to develop evidence-based clinical protocols.

Investigation of potential adverse effects—including impacts on CO₂ sensitivity, the risks of unprocessed emotional material surfacing without adequate support, and the safety profile in clinical populations—remains an important priority.

Conclusion

The research reviewed here suggests that deliberate, controlled manipulation of the breath can produce meaningful changes in stress, anxiety, depression, immune function, mood, and consciousness. These effects are supported by plausible physiological mechanisms and have been documented across multiple breathwork traditions using increasingly rigorous study designs.

At the same time, the field remains young. Effect sizes are typically small to medium in meta-analytic data, most studies carry moderate risk of bias, and the samples studied so far are demographically narrow. The most honest summary of the evidence might be: breathwork appears to work, its effects are real and measurable, and it may offer a valuable complement to existing therapeutic approaches—particularly for individuals who face barriers to conventional treatment—but the precise scope, optimal protocols, and long-term safety profile remain to be established.

What is clear is that breathwork research has reached a tipping point. The days of treating controlled breathing as merely a wellness trend are over. As Fincham and colleagues observed, the scientific trajectory of breathwork may parallel that of meditation two decades ago—a practice once dismissed by the scientific mainstream that went on to amass a formidable evidence base.⁵ Whether breathwork follows the same trajectory will depend on whether the research community can match the public's enthusiasm with the rigour and nuance the subject demands.

Footnotes

1. Fincham, G. W., et al., "High Ventilation Breathwork Practices: An Overview of Their Effects, Mechanisms, and Considerations for Clinical Applications," Neuroscience and Biobehavioral Reviews 155 (2023): 105453, https://doi.org/10.1016/j.neubiorev.2023.105453. ↩

2. Havenith, M. N., et al., "Decreased CO₂ Saturation during Circular Breathwork Supports Emergence of Altered States of Consciousness," Communications Psychology 3, no. 59 (2025), https://doi.org/10.1038/s44271-025-00247-0. ↩

3. Bahi, C., et al., "Effects of Conscious Connected Breathing on Cortical Brain Activity, Mood and State of Consciousness in Healthy Adults," Current Psychology 43 (2024): 10578–10589, https://doi.org/10.1007/s12144-023-05119-6. ↩

4. Nestor, J., Breath: The New Science of a Lost Art (New York: Penguin Life, 2020). ↩

5. Fincham, G. W., et al., "Effect of Breathwork on Stress and Mental Health: A Meta-Analysis of Randomised-Controlled Trials," Scientific Reports 13 (2023): 432, https://doi.org/10.1038/s41598-022-27247-y. ↩

6. Blake, R. L., "Efficacy of Online Conscious Connected Breathwork in Reducing Symptoms of Anxiety: A Randomized Waitlist Control Trial," Journal of Affective Disorders 394 (2026): 120565, https://doi.org/10.1016/j.jad.2025.10.075. ↩

7. Balban, M. Y., et al., "Brief Structured Respiration Practices Enhance Mood and Reduce Physiological Arousal," Cell Reports Medicine 4 (2023): 100895, https://doi.org/10.1016/j.xcrm.2022.100895. ↩

8. Blades, R., et al., "A Randomized Controlled Clinical Trial of a Wim Hof Method Intervention in Women with High Depressive Symptoms," Comprehensive Psychoneuroendocrinology 20 (2024): 100272, https://doi.org/10.1016/j.cpnec.2024.100272. ↩

9. Fox, N., Biddell, H., and King, J., "A Semi-Randomised Control Trial Assessing Psychophysiological Effects of Breathwork and Cold Immersion," Scientific Reports 15 (2025): 43879, https://doi.org/10.1038/s41598-025-29187-9. ↩

10. Fincham, G. W., et al., "Effects of Brief Remote High Ventilation Breathwork with Retention on Mental Health and Wellbeing: A Randomised Placebo-Controlled Trial," Scientific Reports 14 (2024): 16893, https://doi.org/10.1038/s41598-024-64254-7. ↩

11. Zaccaro, A., et al., "How Breath-Control Can Change Your Life: A Systematic Review on Psycho-Physiological Correlates of Slow Breathing," Frontiers in Human Neuroscience 12 (2018): 353, https://doi.org/10.3389/fnhum.2018.00353. ↩

12. Kartar, A., et al., "Neurobiological Substrates of Altered States of Consciousness Induced by High Ventilation Breathwork Accompanied by Music," PLOS One 20, no. 8 (2025): e0329411, https://doi.org/10.1371/journal.pone.0329411. ↩

13. Kox, M., et al., "Voluntary Activation of the Sympathetic Nervous System and Attenuation of the Innate Immune Response in Humans," Proceedings of the National Academy of Sciences 111, no. 20 (2014): 7379–7384, https://doi.org/10.1073/pnas.1322174111. ↩

14. Buijze, G. A., et al., "An Add-on Training Program Involving Breathing Exercises, Cold Exposure, and Meditation Attenuates Inflammation and Disease Activity in Axial Spondyloarthritis—A Proof of Concept Trial," PLOS One 14 (2019): e0225749, https://doi.org/10.1371/journal.pone.0225749. ↩

15. "Take a Breather—Physiological Correlates of a Conscious Connected Breathing Session in a Trained Group of Breast Cancer Patients," Cancers 17, no. 22 (2025): 3690, https://doi.org/10.3390/cancers17223690. ↩

16. Uthaug, M. V., et al., "An Experience with Holotropic Breathwork Is Associated with Improvement in Non-Judgement and Satisfaction with Life While Reducing Symptoms of Stress in a Czech-Speaking Population," Journal of Psychedelic Studies 5, no. 3 (2021): 176–189, https://doi.org/10.1556/2054.2021.00193. ↩

17. Bonnelle, V., et al., "Autonomic Nervous System Activity in the Psychedelic State: Findings from a Controlled Study of DMT and Implications for Psychedelic-Assisted Therapy," Journal of Psychopharmacology (2024), https://doi.org/10.1177/02698811241276788. ↩

18. Pratscher, S. D., et al., "Single-Session Group Breathwork Intervention for Chronic Pain: A Proof-of-Concept Study of Guided Respiration Mindfulness Therapy," Journal of Integrative and Complementary Medicine (2025), https://doi.org/10.1177/27683605251406218. ↩

19. Caddye, E., et al., "Movement-Informed Breathwork (MiB): Integrating Muscular Contractions with Slow Conscious Connected Breathing for Therapeutic Application," OBM Integrative and Complementary Medicine 11, no. 1 (2026): 006, https://doi.org/10.21926/obm.icm.2601006. ↩