Nose Breathing: The Foundation of Every Breathwork Practice
In our work at keur, we begin almost every conversation about the breath with the same simple invitation:
Slow. Low. Light. Through the nose.
A breath that moves quietly into the belly rather than the chest. A breath that asks for less, not more. A breath the body almost forgets it is taking.
When we breathe this way, something significant happens. The body sends a signal to the brain — I am safe. The vagus nerve finds activation. The parasympathetic nervous system engages. The heart rate steadies. The mind softens. The whole organism comes home.
This is the simplest, most continuous form of self-regulation available to a human being. It is also, of all the techniques we teach, from coherent breathing to breath holding to transformational breathwork, the foundation that has to be in place before any of the others can do their work.
Nose breathing is that foundation.
It is the quiet, daily practice that makes every other technique stronger.
It is also, perhaps, the most ancient teaching of all.
An Old Wisdom, Rediscovered
Long before modern pulmonology, the yogis of ancient India understood something profound about the breath. In the Hatha Yoga Pradipika, written more than five centuries ago, we find this line:
"When the breath is unsteady, the mind is unsteady. When the breath is steady, the mind is steady, and the yogi becomes steady. Therefore, one should restrain the breath."
Pranayama, the yogic art of breath regulation, has always been practiced through the nose. The mouth was reserved for eating and speaking. The nose was for breathing, and through it, for life force, for prana.
In Tibetan monasteries, in Daoist temples, in Sufi circles, the same teaching appears again and again: the slow, quiet, nasal breath is the gateway. Everything else is built on top.
What is remarkable is that modern science is now arriving, by very different paths, at the same conclusion.
Why So Many of Us Have Forgotten How to Breathe
Award-winning journalist James Nestor, author of Breath: The New Science of a Lost Art, spent a decade investigating why so many of us struggle with this most basic biological function. His finding is striking: around 90% of us are suffering from some form of respiratory dysfunction (Nestor, 2020). In a recent conversation with Tim Ferriss, he revised the figure even higher, closer to 95%. "It is so rare," he says, "that somebody breathes normally."
Nestor's research traces this collective dysfunction back to something unexpected: industrialised food. As our diets softened over the centuries, our jaws shrank. Smaller jaws meant narrower airways and the now-universal experience of crooked teeth. Combine this with chronic stress, sedentary lifestyles, and screen-bound posture, and the result is a population that has, quite literally, forgotten how to breathe.
The dysfunction is sometimes obvious, snoring, asthma, chronic congestion. But more often, it is subtle. Mouth breathing during the day. Shallow chest breathing at the desk. Hyperventilation under stress. Breathing patterns so familiar that we no longer recognise them as patterns at all.
Even athletes are not exempt. A 2023 study from Ritsumeikan University in Japan screened 1,933 competitive athletesacross multiple sports and found that 90% breathed dysfunctionally — using accessory muscles in the chest and shoulders rather than the diaphragm (Shimozawa et al., 2023). The highest rates were in young athletes still in school. This matches what we have seen in our own work with sponsored global athletes: the ability to push through pain is not the same as the ability to breathe well.
The yogis would not be surprised. They warned of this thousands of years ago. Unsteady breath, unsteady mind. Steady breath, steady being.
The Forgotten Function of the Nose
The nose is not a backup system for the mouth. It is one of the most elegant pieces of human design.
When you breathe through it, the air is filtered, warmed, humidified, and pressurised before reaching the lungs. The turbinates, the spiral structures inside the nasal cavity, slow the airflow and create resistance, encouraging fuller lung expansion and proper engagement of the diaphragm. The mouth simply cannot do this.
But the most fascinating part happens silently inside the paranasal sinuses, where a molecule called nitric oxide is continuously produced.
When you inhale through the nose, you carry this nitric oxide into your lungs. It dilates the airways, opens the small blood vessels in the alveoli, and improves the efficiency of oxygen transfer into your bloodstream (Lundberg & Weitzberg, 2022). It also has antimicrobial properties, helping neutralise bacteria, viruses, and other pathogens before they reach the lungs (Martel et al., 2020).
In other words: the nose is your first line of immune defence.
This is what Dr. Maurice Cottle, the American rhinologist who founded the American Rhinologic Society in 1954, described as the 30+ functions of the nose: from filtering, warming, and humidifying the air, to producing nitric oxide, regulating airflow, supporting immune defence, shaping the jaw and palate, and influencing posture, sleep, and emotional regulation.
The yogis called the nose the seat of prana. The scientists call it a nitric oxide reservoir.
Two languages. The same truth.
Why Nose Breathing Is the Foundation
Most modern humans are over-breathing. Too fast, too shallow, too high in the chest, and too often through the mouth.
When we over-breathe, we exhale too much CO₂. This sounds harmless, but CO₂ is the molecule that allows oxygen to be released from haemoglobin into your tissues. This is known as the Bohr effect, named after the Danish physiologist Christian Bohr who described it in 1904.
Lower CO₂ tolerance means less oxygen reaching your cells, even when blood oxygen saturation looks fine on paper.
Nose breathing naturally slows the breath, lowers respiratory rate, and gradually rebuilds CO₂ tolerance. It is, quite literally, the practice that retrains the nervous system to breathe in a way that is sustainable for life.
This is why we ask every student, every athlete, every executive who walks into our space the same question before anything else: How is your nose breathing?
The BOLT Score: A Compass for the Practice
Before introducing more advanced techniques like breath holds or transformational breathwork, we like to know where someone is starting from.
The simplest tool we use is the BOLT score (Body Oxygen Level Test), a brief breath-hold measure used in breathwork practice and research as a simple field assessment of CO₂ tolerance and breathing efficiency.
How to measure your BOLT
Sit quietly for a few minutes and breathe normally through the nose
After a normal exhale, pinch your nose
Time how long until you feel the first definite urge to breathe (not the maximum hold)
Release and resume normal nasal breathing
Interpreting the result
Under 10 seconds — significant breathing inefficiency, often linked to stress, anxiety, or poor sleep
10–20 seconds — below average, common in modern lifestyles
20–30 seconds — the range where research considers breathing functional; a good baseline for further training
40 seconds — optimal CO₂ tolerance and breathing efficiency
A note of intellectual honesty: a 2024 study found that BOLT scores did not correlate with exercise performance in elite athletes (Mackała et al., 2024). BOLT is not a predictor of athletic output. What it is — and this is how we use it in practice — is an honest snapshot of where someone is at with their breathing in this moment. A starting point. A reference. A self-tracking tool for breathing efficiency, CO₂ tolerance, and the calmness of the respiratory system.
In our trainings, we recommend bringing your BOLT score into the 25 second range through consistent nose breathing and slow-breathing techniques before adding intensity-based techniques. This is the threshold where the body has adapted enough to safely build into deeper work.
Three Reasons Nose Breathing Belongs at the Centre of Your Practice
1. Sports Performance and Recovery
The most counterintuitive truth in modern sports performance is one the ancient yogis already understood: breathing less often makes you stronger.
A landmark study by Dallam and colleagues found that runners training for six months with nasal-only breathing matched their oral breathing performance, same VO₂max, same time to exhaustion, but with significantly better breathing economy (Dallam et al., 2018). They did the same work using less breath.
This matches what we see in our Sports Performance + Resilience workshops, and in our work with On's sponsored global athletes. When athletes commit to nasal-only breathing during easy and moderate training, three things consistently happen: respiratory rate drops, perceived effort decreases, and recovery between sessions improves.
The mechanism is elegant. By breathing slower and lighter through the nose, the body gradually builds CO₂ tolerance, the foundation of efficient breathing. Higher CO₂ means better oxygen release into the muscles (the Bohr effect), and more recruitment of the diaphragm.
The downstream effects reach further than performance alone: better recovery between sessions, deeper sleep, steadier energy, and a calmer emotional baseline. There is also a quieter benefit — when breathing becomes more efficient, less blood is diverted to the respiratory muscles, leaving more available for the muscles that are actually doing the work
2. Sleep
If you wake with a dry mouth, fatigue that no amount of coffee fixes, or a partner who tells you that you snore, there is a high chance you are mouth breathing at night.
Sleep is when the nervous system repairs itself. But that repair only happens when breathing is calm, slow, and quiet. Mouth breathing during sleep is associated with increased snoring and risk of sleep-disordered breathing, fragmented sleep architecture, lower oxygen saturation overnight, and daytime fatigue.
Nestor himself ran a now-famous experiment at Stanford. For ten days, his nose was completely plugged so he could only breathe through his mouth. His snoring increased over thirteenfold, his blood pressure spiked, and his cognitive function dropped measurably. When he switched back to nasal breathing, and used mouth tape at night, every marker reversed within days.
There are two places to begin: during the day, by gently keeping the mouth closed at work, on walks, and at rest — and at night, through mouth taping, a small piece of breathable tape across the lips that keeps the breath in the nose during sleep. Build it up gently, try it for a bit during some computer work first, then through the night. The more hours you spend nose breathing, the more naturally the body returns to its design.
If you struggle to fall asleep, you may also enjoy our previous article: How Can I Fall Asleep Faster?
3. Sustained Energy and Calm Focus
The most common feedback we hear after even one week of conscious nose breathing is this: "I feel more steady."
Not high-energy. Not euphoric. Steady.
Slow, nasal, diaphragmatic breathing engages the parasympathetic branch of the nervous system through vagal pathways, increasing heart rate variability and downregulating the stress response (Russo et al., 2017). The result is energy that does not crash. The kind that gets you through a long meeting, a difficult conversation, or a demanding training session without depleting you.
When you breathe through the mouth, you stay in a low-grade fight-or-flight loop all day. Switch to the nose, and you signal to the body, again and again: I am safe. I can think. I can be here.
Dysfunctional Breathing, Sleep, and Attention
There is one area of research we want to highlight carefully, because we believe it is one of the most important and most underdiscussed health stories of the last decade.
A growing body of evidence links mouth breathing and sleep-disordered breathing to symptoms that closely resemble, and may be misdiagnosed as, ADHD, particularly in children. Nestor reports that some sleep medicine specialists now believe many ADHD diagnoses are, in fact, undiagnosed sleep-disordered breathing.
A 2021 study assessing 100 children with persistent mouth breathing found that daytime sleepiness correlated significantly with inattention, shorter sleep duration correlated with hyperactivity, and seven children met the full clinical criteria for ADHD. The authors concluded: "Children with sleep disturbances or ADHD should be assessed for the presence of mouth breathing, as early identification and correction of mouth breathing may help to prevent unnecessary exposure to medication" (Kalaskar et al., 2021).
This builds on a much larger body of evidence. A meta-analysis found that ADHD-like symptoms in children with sleep-disordered breathing improved significantly after surgical removal of the obstructions that force mouth breathing (Sedky et al., 2014).
We want to be careful here. We are not saying nose breathing cures ADHD. ADHD is a complex neurodevelopmental condition. What the research does clearly show is that a meaningful subset of attention and behavioural symptoms, in both children and adults, may be driven by, or worsened by, dysfunctional breathing and the sleep disruption it causes.
If you, your child, or someone you love is struggling with attention, focus, or sleep, looking at the breath is not a substitute for proper medical evaluation. But it is, in our view, a missing piece of the conversation that deserves to be on the table.
The Quiet Power of a Closed Mouth
We live in a culture that tends to associate strength with intensity. Bigger breath. Harder effort. More output.
Nose breathing reminds us of something different.
That the deepest performance, physical, mental, emotional, comes from efficiency, not intensity. From breathing slower, not faster. From doing less, not more.
The yogis knew this. The monks knew this. The freedivers know this. And now the science is catching up.
As Nestor puts it: "The most helpful thing you can do for yourself is just to be a normal breather."
This is what we mean when we say breath is the foundation. Not a technique you perform. A way you live.
A return to something you already know.