My Lifelong Fascination With Breathing Began at Five
Insights from a seasonaly snotty child.
I grew up in Canberra, a windy town where ryegrass pollen filled the air. Each spring I was the snotty, allergic child — eyes rubbed raw, corneas swollen to jelly, nose itchy, half blocked. Nights were the hardest. I hated going to bed because it meant lying there, struggling to breathe through a nose that refused to open.
I didn’t like breathing through my mouth I think I’d figured out that it would make my throat sore. So I worked hard to breathe through my nose and found that if I persistently slowed my breath, a little passageway opened. Later I understood why. By slowing my breath I was retaining CO₂, and that CO₂ relaxed the smooth muscle in the nasal passages. The airway opened. I thought I’d found a trick, but really, I was already working with physiology.
Slower breath → more CO₂ → airway opens.
The Diver
By thirteen I was scuba diving with adults. Because I was smaller, I breathed faster and was always the one to run out of air first — the one to pull the “reserve” lever that meant the whole dive was over.
During a club treasure hunt, I was determined to not run dry fast and decided to try something different: I would breathe every second breath. And it worked. My tank lasted and lasted. I stayed down until boats were out searching for me.
Again, the physiology was there. By slowing my breathing, I was using less air. People might think holding back like this would be dangerous — that I’d get lightheaded or sick. But I didn’t. I felt normal. The reason: I was retaining CO₂, and that prevented my cerebral blood vessels from constricting. No headache, no harm. My experiments were teaching me about breathing physiology.
Every second breath → more CO₂ retained → less air wasted → no harm done.
The Nurse
By my early twenties I was working in paediatric ICU. There I saw the opposite lesson. After suctioning or turning a child with severe head injury, their intracranial pressure would spike. One of the quickest tools we had was to bag them — to deliver a few fast breaths.
It worked because more breathing lowered CO₂, and that constricted the smooth muscle in their blood vessels, reducing cerebral blood flow. With less blood pushing into the brain, the pressure came down.
Another vivid demonstration of the same mechanism, this time in life-and-death conditions.
Faster breath → CO₂ lost → vessels constrict → cerebral blood flow drops.
The Sleep Clinic
“When I wake up, I feel like my head is empty.”
That was how one woman described her mornings when I worked in a sleep clinic. It wasn’t poetry. She was giving a perfect physiological account of what happens when the brain is starved of blood flow and oxygen through the night.
What she said in words was what I saw in countless others on the monitor: the same fast, shallow breathing, the same CO₂ loss, the same obstruction. The only difference was that she described it perfectly.
On the monitor we could see she was obstructed and mouth breathing. Her teeth told the same story: a mouth breather, not a nasal breather. Lying down, she lost the advantage of gravity. Already congested from a fast breathing pattern, she blew off CO₂ constantly. The loss of CO₂ made smooth muscle tighten — in the diaphragm, in the airway walls, even in blood vessels. Congestion increased as blood was pushed into the vascular lining of the upper airway. The soft palate sagged back, further closing the throat. The sound was familiar: snoring.
Overnight, the cycle reinforced itself. CO₂ continued to fall, smooth muscle continued to constrict, the effective size of the “breathing bag” shrank smaller and smaller. Airway obstruction worsened. Blood vessels narrowed. Less blood — and less oxygen — reached the brain.
Her words came back to me: empty. That was exactly what she was. Empty of blood flow, empty of oxygen. She was, in effect, bagging herself all night long, the way I had once bagged head-injured children in ICU.
Fast, shallow breath → CO₂ falls → smooth muscle tightens → brain blood flow reduced.
Fast breath = less CO₂ = less flow.
Slow breath = more CO₂ = more flow.
CO₂ not waste — it is the regulator.
A Thoughtful Child’s Thread
These memories never faded. They stood out because they were always pointing me in one direction: toward understanding breathing.
I know I’m not alone in that. Some children latch onto a “thing,” and it never leaves them. I met Mark Paul when he installed our roof garden. He went on to found The Greenwall Company, and he has explained how his lifelong work with plants began with a childhood fascination for lithophytes — plants that grow on rock.
When I heard him say that, I recognised something in his “thinking type” that felt like my own. My “thing” was breathing. That was the thread that never let me go.
Buteyko
Years later, working in asthma and allergy, I saw it confirmed in front of me. A young woman undergoing a histamine challenge refused Ventolin after her lung capacity had dropped 40%. Instead, she asked to do her breathing exercises. Within minutes her lung function improved, better than any point in the test. I asked what she had done. She said: Buteyko.
From that moment, I began to study Buteyko seriously. I fixed my own nose first. I fixed my children’s. I desensitized many people and taught them the advantages of nasal breahting. With my own eyes, I saw what I had sensed as a child: slowing the breath and using the nose changes blood chemistry and improves whole-body function.
Breath steers the nervous system. It shifts us towards parasympathic dominance, towards calmer physiology, better blood flow to the core organs, and steadier growth, and healing. I charted the children’s growth on percentile charts - they returned to their initial birth percentiles. They were calmer. They healed better.
In the allergy unit we had discovered what my body had always known: breath is the governor of physiology. Our breathing history is written in our teeth — crooked, crowded or decayed — the giveaway signs of mouth breathing. But the message is not diagnostic, it is hopeful. We all have the capacity to change our own health with every breath we choose to take through the nose.
About the Author:
Catherine Broué works with the body as a whole system, focusing on breath and the nervous system. After two decades in ICU and dialysis, she turned to the deeper question of real health, guided by mentors and the insights of Christian Bohr and Konstantin Buteyko. Her work centres on the body’s true regulators — breath and the central nervous system — and the return to parasympathetic dominance.