A breathing technique commonly practised during yoga could potentially be used as a treatment for brain disorders, including depression.
New research from the Auckland University of Technology (AUT) BioDesign Lab has found that 'yoga breathing' - breathing through one nostril at a time - alters the activity in the brain. The technique, familiar to many devotees of the discipline, is popular in yoga classes and is usually controlled by hand.
The research, led by research fellow and Director of Research for the New Zealand College of Chiropractic (NZCC) Dr Imran Khan Niazi and Associate Professor David White, shows that changes in brain activity can be measured in response to yogi nasal breathing.
The researchers found that breathing through the right nostril is involved in relatively higher sympathetic activity, or arousal states, while breathing through the left nostril is associated with a relatively more parasympathetic state, or stress-relief.
In simple terms, this means breathing through the right nostril could help to energise people, while breathing through the left nostril could help people find a calmer mental state.
Associate Professor White - co-director of the BioDesign Lab - said this first stage of research confirms the relationship between unilateral nasal breathing and brain activity, paving the way for further research.
The breathing technique is now being explored as a treatment for brain disorders, including depression, Prof White said, and could possibly be used to help autistic people and those with degenerative diseases.
"We can see that this process, using our device to regulate the pattern of breathing, is a big leap forward in potential therapies," Prof White said.
"There is a spectrum of health outcomes breathing protocols could deliver, including clinical treatment and potentially enhanced mental and physical performance. Initially we are exploring the treatment of brain disorders including depression, but this treatment could be used to help autistic people, as well as those with degenerative diseases or traumatic brain injuries."
The research used the BioDesign Lab's RACer system to regulate the airflow between each side of the nose over 10 minute periods, capturing electro-encephalogram (EEG) data. RACer is a medical device that delivers breathing therapy to the patient, without needing to physically hold the nostrils with the hand as in yoga.
The study shows both hemispheres of the brain become equally aroused during right nasal breathing, which induces an excited state, and equally attenuated with left nasal breathing, which induces a calming state.
Dr Niazi said the salient finding of the study demonstrates the impact of left nasal breathing.
"Left nasal breathing is associated with a prominent posterior rhythm in all brain waves except gamma, which is associated with a more relaxed state and introspective thinking," he said.
Prof White added that the study opens up a range of exciting treatment options and researchers are now focused on patient outcomes.
"We now can show a link between the act of breathing through one nostril at a time on brain activity and this opens up exciting treatment options.
"We are working to develop a way to use an algorithm alongside a medical device with RACer that provides feedback on brain activity performance and through an algorithmic feedback loop adjusts its breathing therapy over time."
The research was published in Nature: Scientific Reports in January 2022.