While breathing techniques that are intensive are typically thought of for relaxation, emotion, and mediation, new brain-imaging research is indicating certain intensive breathing exercises might cause significant changes in blood flow to the brain as well as interesting altered states of consciousness.
Researchers conducted the study with others at the Yale University School of Medicine in Progress in Neuro-Psychopharmacology & Biological Psychiatry in August 2026. In high-ventilation breathwork, the individual maintains a rapid, deep breathing pattern for some time to alter their subjective experience. The team determined that total grey-matter cerebral blood flow decreased by 45.5% in the strongest part of the experience.
The study team examined 30 professional breathwork practitioners, with a mean age of around 45 years. Participants had MRI scans, plus more targeted scans, that can assess blood flow in the brain, performed. Measurements were made before and during the state where practitioners said they felt the strongest effects.
The team reported an average reduction in blood flow in the brain of about 29.81 to 16.24 millilitres per 100 grams of grey matter per minute. They saw increases in heart and breathing rates during the sessions.
Participants reported changed experiences, like visualization, perception shifts, and better mindfulness of their environment. Some of these experiences were similar to reports of altered consciousness in psychedelic research, but they were not a part of the current study.
The results are a concrete demonstration that high-ventilation breathwork can have an impact on the physiology of the brain. The study could also give scientists a method to study the impact that changes in breathing have on consciousness without administering drugs.
Besides assessing cerebral blood flow, the researchers also assessed the activity of the default mode network, a set of brain regions that are highly interconnected and that engage in many states of rest such as self reflection and memory retrieval.
No statistically significant overall change in default mode network connectivity was observed following breathwork. But, exploratory analysis indicated that more severe altered states were related to greater reductions in default mode network connectivity for some participants.
That relationship was influenced by the statistical technique and was not statistically significant in an alternative analysis. The researchers also observed that the magnitude of the blood-flow reduction did not consistently correspond to the strength of an individual’s subjective response.
This difference indicates that decreased blood flow and altered brain-network communication could be separate components of the breathwork experience and not a single pathway responsible for all of the effects.
Breathing can affect carbon dioxide levels in the blood. Over-breathing can lower carbon dioxide levels, leading to hypocapnia, which can result in constricted blood vessels in the brain, leading to a reduction in blood flow to the brain.
These variations might cause sensations of light-headedness paresthesias visual anomalies, and a sense of unreality. These things may account for why extreme breathing practices may occasionally lead to intense subjective experience.
Though these findings are intriguing, the new research wasn’t intended to demonstrate that getting less blood flow is a good thing. Just because we saw a huge physiological change doesn’t mean our brain functioning or future health is any better.
