What Happens in Your Body During Conscious Connected Breathwork

You’re lying on a mat, breathing in a consciously connected rhythm. After a while, your hands begin to tingle and warmth moves through your body. Tears come without a clear reason and later you might find yourself filled with a deep sense of connection. You might wonder: What is actually happening in my body?

Most breathwork research has focused on slow breathing, typically below 10 breaths per minute, which is associated with increased parasympathetic activity and relaxation. Fast, connected breathing is far less studied, with researchers only recently beginning to examine its effects on the body and brain.¹

Some of this renewed interest comes from psychedelic research. Psychedelic-assisted therapies can produce profound altered states and clinical trials have reported promising effects for conditions such as depression and PTSD. But access remains limited by legal, medical and financial barriers. Could breathwork evoke some of the same psychological processes with nothing but the air we breathe?²

To piece this together, I’ve drawn on recent studies that each illuminate a different part of the process, from the first changes in CO₂ to shifts in the brain, mood and experience afterwards.

Ancient roots, modern forms

Fast breathing to heal or shift consciousness is much older than modern breathwork. High-ventilation practices have been described across Sufi and some Indigenous North American traditions, as well as in yogic pranayama such as Kapalabhati and Bhastrika. Tibetan Tummo combines breathing practices with visualising inner heat.

Modern breathwork began taking its own forms in the 1960s and 1970s. Leonard Orr created Rebirthing, while Stanislav and Christina Grof developed Holotropic Breathwork. Grof’s approach emerged partly as another route into non-ordinary states after LSD could no longer be used in his therapeutic work. Other approaches followed, while the Wim Hof Method later brought intensive breathing to a much wider audience.¹

Circular breathing, or conscious connected breathing, connects inhale and exhale into one continuous rhythm, without a pause in between. Sessions are often done lying down and accompanied by music and guidance. As attention turns inward, emotions, movement, sound or memories may surface.^1,2,3

What happens when CO₂ falls

When you breathe faster or deeper than your body needs, you exhale CO₂ faster than you produce it. As CO₂ falls, blood pH rises, making the blood more alkaline. This is known as respiratory alkalosis.

Low CO₂ causes blood vessels in the brain to constrict, reducing cerebral blood flow. At the same time, haemoglobin holds on to oxygen more tightly. So even though you are breathing more, oxygen delivery to the brain can actually decrease.

This shift in blood chemistry also affects the nervous system. As the blood becomes more alkaline, ionised calcium decreases, which makes nerve cells more excitable. This helps explain sensations such as tingling, trembling, muscle tension and the characteristic curling of the hands that can sometimes happen during intensive breathwork.

At the same time, the body becomes more activated. Sympathetic nervous system activity can increase and stress hormones may be released, creating a short-term state of heightened arousal.

If the breathing continues, these changes do not simply become stronger. The physiology becomes more complex over time, and exactly what happens during prolonged fast breathing is still not fully understood.¹

CO₂ as the trigger for altered states

Knowing what low CO₂ does to the body is one thing. Showing that it actually relates to the experience is another.

A recent study followed 61 experienced participants during Holotropic and Conscious Connected Breathwork sessions. Some were instructed to breathe normally while taking part in the same sessions, with the same music, group environment and facilitators. This allowed the researchers to begin separating the effects of the breathing itself from those of the setting.

Researchers repeatedly measured end-tidal CO₂ and asked participants to rate the depth of their experience, from ordinary waking consciousness to deeply altered states.

The lower CO₂ fell, the deeper the experience tended to become. In fact, there appeared to be a kind of threshold. While CO₂ stayed within its normal range of around 35 mmHg or more, intense altered states were rare, whereas below roughly 20 mmHg almost everyone moved beyond ordinary waking consciousness.

CO₂ usually reached its lowest point during the first half of the session and then started to rise again, while the altered state often continued. This suggests that the drop in CO₂ may help trigger the experience, rather than having to maintain it throughout.

This may help explain why the experience can stay deep even as the physiology begins to settle. The breath sets something in motion, and then the experience continues to unfold.

But CO₂ was not the whole story. Even participants who breathed normally reported milder shifts in consciousness. Music, the presence of other people, facilitation and the atmosphere of the room seemed to matter too. And because the participants were experienced breathers, familiarity and expectation may also have played a role.²

Inside the brain while you breathe

What does all this look like inside the brain? In a small MRI study with 13 experienced breathers, researchers tracked blood flow in the brain and how deeply altered the experience felt.

During breathwork, overall cerebral blood flow dropped substantially. One of the strongest links to subjective experience appeared in the posterior insula, a region involved in sensing what is happening inside the body. The greater the reduction in blood flow there, the stronger participants reported feelings of unity and bliss.

The amygdala and hippocampus showed a different relationship. Even though overall cerebral blood flow decreased, relatively higher blood flow in these regions was linked to deeper experiences. Since these areas are closely involved in emotion and memory, this may offer one clue as to why feelings or memories can become especially vivid during breathwork.

Another theory focuses less on specific brain regions and more on how the brain processes signals from the body. During prolonged fast breathing, the body sends signals that would normally slow the breath down, while the person deliberately continues breathing. This mismatch may contribute to shifts in the usual sense of self.^1,4

Brain waves after the session

What remains once the breathing stops? One study with 20 adults measured resting EEG activity and mood before and after a 45-minute Conscious Connected Breathing session.

After the session, activity in several lower-frequency brain rhythms had decreased. Delta, one of the slowest brain rhythms and strongest during deep sleep, has also been linked to lower brain activity when we are awake. Its decrease after breathwork may therefore reflect a shift towards a more activated state.

Theta is involved in memory encoding and problem solving, while unusually high activity has also been linked to avoidance and neuroticism. Its activity decreased too, which the authors suggest may reflect a more open, less self-focused state.

The lower beta bands, which have been connected to stress, anxiety and rumination, fell as well.

Only in the small subgroup of experienced breathers did a fast rhythm called gamma increase, a change also reported in research on meditation and psychedelic or ketamine states, though these parallels are still preliminary.

Also, mood shifted alongside the EEG. Participants reported less tension, confusion and depressed mood, while self-esteem increased. Notably, the larger the reductions in delta and theta, the greater the drop in depressive mood scores.³

In the days after

The earlier study on CO₂ and altered states also looked at what happened beyond the session itself. One week later, active breathers reported better overall well-being and fewer depressive symptoms. Deeper altered states during the session were associated with greater improvements afterwards.

The body showed a more mixed response. Alpha-amylase, a marker related to sympathetic nervous system activity, decreased after the session in active breathers. This may suggest that the body was moving out of its more activated state and back towards relaxation by the end of the session.

At the same time, the inflammatory marker IL-1β increased. Interestingly, this change was smaller in participants who reported deeper experiences. The researchers discuss this rise as a possible short-term physiological challenge. One possible interpretation is hormesis, the idea that a brief physiological stressor such as exercise or fasting can trigger adaptive responses and potentially increase resilience over time. For breathwork, however, this remains a hypothesis that needs longer-term study.²

Breathwork and psychedelics: how do they compare?

One reason breathwork has attracted growing scientific interest is its overlap with psychedelic states. Researchers have used measures common in psychedelic research, such as the 11-Dimensional Altered States of Consciousness questionnaire (11D-ASC), to compare the experiences.

In one study, breathwork showed its strongest overlap with psilocybin in Oceanic Boundlessness, a dimension that includes unity, bliss, spiritual experience, insight and shifts in the usual sense of self. Scores across these subscales resembled those reported after higher doses of psilocybin, while perceptual changes were closer to medium-dose patterns.

Rather than strong visual distortion, one of the most prominent changes was in how meaningful or personally significant perceptions felt. Feelings related to fear and loss of control remained low relative to the other dimensions of the breathwork experience.

A second study found a similar pattern, with active breathwork approaching scores reported after around 20 to 25 mg of psilocybin on several measures of altered and mystical experience.

These comparisons are intriguing, but they do not mean breathwork and psilocybin produce the same experience. The psychedelic reference scores came from separate studies rather than direct head-to-head experiments, so they show similarities in reported experience rather than equivalence.^2,3

What the research can’t tell us yet

The science is still young. Studies are generally small, control groups are rare and follow-up periods are short, so we still know relatively little about how consistent or lasting these effects are. Several studies also involved experienced breathers, making it difficult to separate the effects of the breathing itself from familiarity and expectation.^1,2,3,4

The research is promising, but there is still a lot we do not understand about what happens during breathwork and why.

Putting it together

Fast, connected breathing lowers CO₂, shifts blood pH and reduces cerebral blood flow. As CO₂ falls, consciousness can begin to shift, and that altered state may continue even as CO₂ starts to recover.

Inside the brain, blood flow changes in regions involved in body awareness, emotion and memory. This may offer clues as to why experiences of unity, strong emotion or emotionally significant memories can emerge. After the session, changes in brain activity were also accompanied by shifts in mood, while another study found better well-being and fewer depressive symptoms one week later.

But physiology is only part of the story. Music, setting, support and the depth of the experience all seem to shape what unfolds. The breath may open the door, while the space around it helps shape the journey.^1,2,3,4

What we can already see is that something as simple as changing the way we breathe can produce measurable shifts in body chemistry, brain function and consciousness.

I find this research fascinating because it offers another way of looking at practices that have been explored experientially for a long time, but can be hard to explain. Knowing a little more about what might be happening in the body doesn’t make any of it feel less mysterious to me. If anything, it makes me even more curious.

Sources

1. Fincham, G. W., Kartar, A., Uthaug, M. V., Anderson, B., Hall, L., Nagai, Y., Critchley, H., & Colasanti, A. (2023). High ventilation breathwork practices: An overview of their effects, mechanisms, and considerations for clinical applications. Neuroscience & Biobehavioral Reviews, 155, 105453.
   https://doi.org/10.1016/j.neubiorev.2023.105453
2. Havenith, M. N., Leidenberger, M., Brasanac, J., et al. (2025). Decreased CO₂ saturation during circular breathwork supports emergence of altered states of consciousness. Communications Psychology, 3, 59.
   https://doi.org/10.1038/s44271-025-00247-0
3. Bahi, C., Irrmischer, M., Franken, K., Fejer, G., Schlenker, A., Deijen, J. B., & Engelbregt, H. (2024). Effects of conscious connected breathing on cortical brain activity, mood and state of consciousness in healthy adults. Current Psychology, 43, 10578–10589.
   https://doi.org/10.1007/s12144-023-05119-6
4. Kartar, A. A., Horinouchi, T., Örzsik, B., et al. (2025). Neurobiological substrates of altered states of consciousness induced by high ventilation breathwork accompanied by music. PLOS One, 20(8), e0329411.
   https://doi.org/10.1371/journal.pone.0329411

This article is for information only and is not medical advice. Fast, high-ventilation breathing is not suitable for everyone and may carry particular risks for people with certain health conditions. If you have a medical condition, speak to a qualified healthcare professional before practising.