How high ventilation breathwork alters consciousness: Hypoperfusion, network dynamics, and subjective experience

High-ventilation breathwork produced a profound altered state of consciousness accompanied by a ~45% reduction in cerebral blood flow,

In this study researchers investigated the neurobiological basis of altered consciousness produced by high-ventilation breathwork (HVB). Specifically, the researchers examined cerebral blood flow, default-mode-network (DMN) dynamics, and their relationship with participants' subjective altered-state experiences.

Key findings

• 30 experienced HVB practitioners participated.

• During the breathwork-induced altered state, global grey-matter cerebral blood flow decreased by ~45.5%.

• This occurred alongside increased respiratory and heart rates.

• There was no significant group-level change in DMN functional connectivity following breathwork.

• Exploratorily, greater reductions in DMN connectivity were associated with stronger subjective altered-state experiences, but this relationship was dependent on global signal regression.

• The magnitude of cerebral hypoperfusion was not associated with the intensity of the subjective altered state.

• The results therefore suggest that changes in cerebral perfusion and changes in brain-network dynamics may contribute differently to HVB-induced altered consciousness, rather than there being a simple “more hypoperfusion = more intense experience” relationship.

Abstract

High ventilation breathwork (HVB) is increasingly used in psychotherapeutic and contemplative contexts to induce altered states of consciousness (ASC), yet its neurobiological mechanisms remain poorly understood. Thirty experienced HVB practitioners (mean age 44.97 ± 11.80 years) underwent perfusion and resting-state fMRI to assess acute cerebrovascular and post-acute network changes.

Cerebral blood flow (CBF) was measured using arterial spin labelling during baseline and the interval of maximal subjective effects. Acute psychotropic effects were rated using an online Likert scale, ASC intensity was assessed immediately after breathwork with the 5-Dimensional Altered States of Consciousness (5D-ASC) scale. HVB induced a 45.5% reduction in global grey matter cerebral blood flow (CBF; 29.81 ± 7.58 vs. 16.24 ± 4.35 milliliter/100 g/min; t(29) = -10.69, p < 0.001), accompanied by increased heart and respiratory rate. Default mode network (DMN) functional connectivity (FC) did not change significantly at the group level. In further exploratory analyses, greater decreases in DMN FC (pre - post breathwork) predicted higher 5D-ASC rating (β = -4.88, p < 0.05) in analyses using global signal regression, though this association was not significant without global signal regression (p = 0.75).

CBF reductions were not associated with ΔDMN-FC or 5D-ASC ratings. HVB produces marked global cerebral hypoperfusion without systematic DMN FC changes, suggesting that hypoperfusion and network dynamics may represent partially dissociable mechanisms underlying breathwork-induced ASC.

As a controllable, non-pharmacological means of inducing ASC, HVB may hold promise as a psychotherapeutic and psychedelic-adjacent intervention.

Schmitz CN, Bernardic M, Vlădoiu AD, Harris R, Carmana D, Kärtner L, Oberthür G, Gründer G, Adolphi H. How high ventilation breathwork alters consciousness: Hypoperfusion, network dynamics, and subjective experience. Prog Neuropsychopharmacol Biol Psychiatry. 2026 Aug 1;149:111873. doi: 10.1016/j.pnpbp.2026.111873. Epub ahead of print. PMID: 42542287. Read Paper

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