Breathing is essential for survival, but taking in a breath of fresh air does more than just keep us alive.

"Breathe in… Breathe out…"

It's common knowledge that taking deep breaths can help calm us down in stressful situations. But now, Professor Micah Allen from the Department of Clinical Medicine at Aarhus University has made significant strides in understanding the relationship between breathing and the brain.

By synthesizing results from numerous studies on the brain imaging of rodents, monkeys, and humans, Allen and his team developed a computational model that explains how our breathing patterns can shape the expectations of the brain.

The study suggests that breathing is more than just something we do to stay alive, explains Micah Allen.

"It suggests that the brain and breathing are closely intertwined in a way that goes far beyond survival, to actually impact our emotions, our attention, and how we process the outside world. Our model suggests there is a common mechanism in the brain which links the rhythm of breathing to these events."

Breathing can affect our mental health

Understanding how breathing shapes our brain, and by extension, our mood, thoughts, and behaviors, is an important goal in order to better prevent and treat mental illness.

"Difficulty breathing is associated with a very large increase in the risk for mood disorders such as anxiety and depression. We know that respiration, respiratory illness, and psychiatric disorders are closely linked. Our study raises the possibility that the next treatments for these disorders might be found in the development of new ways to realign the rhythms of the brain and body, rather than treating either in isolation," explains Micah Allen.

Stabilizing our mind through breathing is a well-known and used tactic in many traditions such as yoga and meditation. The new study sheds light on how the brain makes it possible. It suggests that there are three pathways in the brain that control this interaction between breathing and brain activity. It also suggests that our pattern of breathing makes the brain more "excitable", meaning neurons are more likely to fire during certain times of breathing

New research to come

The new study gives researchers a new target for future studies in for example persons with respiratory or mood disorders, and Micah Allen and his group already have already started new projects based on the study.

"We have a variety of ongoing projects that are both building on and testing various parts of the model we have proposed. Ph.D. Student Malthe Brændholt is conducting innovative brain imaging studies in humans, to try and understand how different kinds of emotional and visual perception are influenced by breathing in the brain," says Micah Allen.

The team is also collaborating with the Pulmonology team at Aarhus University Hospital, where tools developed in the lab are used to understand whether a person suffering from long-covid may have disruptions in the breath-brain alignment. And there are more projects coming, says Micah Allen.

"We will be using a combination of human and animal neuroimaging to better understand how breathing influences the brain, and also utilizing exploring how different drugs influence respiratory-brain interaction. We would also like to someday study how lifestyle factors like stress, sleep, and even things like winter swimming influence breath-brain interaction. We are very excited to continue this research," says Micah Allen.