Deep Dive
How Nestor's Book Became Far Deeper Than Planned
James Nestor starts by recounting his publishing journey—he had a clear proposal and sold it to a publisher with just enough advance money to barely get by. But fieldwork revealed the plan was fundamentally wrong. He spent two years traveling and researching before realizing the story of how humans lost functional breathing was ten levels deep, not three. This forced a complete rewrite and loss of two years of research and travel expenses. Nestor explains that despite modern tools and AI, you cannot find the real truth online; you must spend years in the field talking to people and uncovering the deeper layers. The rewrite cost him time and energy but ultimately resulted in a far more important story. Patrick McKeown notes the quality difference is visible in the finished book, and despite the upfront risk—the book could have sold only 5,000 copies—it ended up selling several million. Nestor acknowledges he considered shelving the project entirely but persisted because living without something to think about felt vacant.
Why Breathing Was Overlooked and Labeled 'Woo'
McKeown asks why breathing has received so little mainstream attention despite being essential to life. Nestor attributes it partly to branding: breathing improvement got associated with crystals, robes, and New Age spirituality, making it seem flaky. Doctors also lack time—seeing 15 patients per hour leaves no room to discuss lifestyle fundamentals. But the bigger issue is willful ignorance. Nestor notes that breathing work has marketed itself poorly, making the field seem unreliable. McKeown adds that he spent 25 years teaching the Buteyko method and constantly faced resistance, including a CEO of the Irish Asthma Society who sat beside him at a 2005 conference specifically to silence him during a panel discussion. Neither speaker blames doctors for past knowledge gaps—they blame the system for discouraging curiosity. Nestor says he's learned that many doctors simply repeat what they were taught and resist new evidence. The two agree that modern medicine needs to follow scientific thinking, which requires questioning everything and updating beliefs when evidence changes, not defending old positions out of pride.
Carbon Dioxide: The Misunderstood Essential Gas
Nestor dedicates significant effort in his book to explaining CO2's role, carefully fact-checking with doctors, biochemists, and chemists because the topic inverts conventional wisdom: hyperventilation doesn't give you more oxygen, it removes CO2 and reduces oxygen availability. McKeown confirms this is straightforward physiology—the Bohr effect, documented since 1904 in every medical textbook's oxygen dissociation curve, proves CO2 is essential for oxygen release to tissues. Hyperventilation floods the system with oxygen but the hemoglobin holds onto it because CO2 levels drop. Nestor initially hesitated to expand on CO2 therapy because it sounded conspiratorial, but discovered a 600-page book by a doctor documenting how CO2 therapy was systematically buried by anesthesiologists in the 20th century because it threatened their turf. Recently, new research shows inhaled CO2 may help Alzheimer's through intermittent hypercapneia—elevated CO2 causes vasodilation, increased brain blood flow, and movement of cerebrospinal fluid that clears amyloid beta toxins. McKeown mentions this aligns with a recent study by Safhira Ryman at University of New Mexico. Both acknowledge people can achieve CO2 benefits through simple breath-holding techniques without machines, but admit machines crack open curiosity doors for people unwilling to do the work.
Two Different Paths, Nearly Identical Destination
McKeown asks Nestor directly what breathing did for him—sleep, stress, anxiety, athletic performance, or facial growth. Nestor responds by saying it changed everything simultaneously, so much so that he feels he lived two different lives before and after. The regret is learning this late; if he'd known at eight, sixteen, or twenty-five, life would have been radically different. McKeown then reveals his own path: he used gentle hypoventilation and reduced breathing to lower his chronic overbreathing, with his resting heart rate dropping from 80 bpm at age 26 to much lower levels. Nestor admits he came in the opposite direction—through extreme Kundalini breathing and hyperventilation that initially blew his mind. Yet they've arrived at the same practical conclusion. McKeown notes they agree on about 95% of the approach, with maybe a 5% personal preference difference, much like the vegan-versus-carnivore nutrition debate: both sides agree on avoiding processed food, then differ on the details. Nestor uses a music wheel analogy—different chords, same wheel. The core agreement is breathing through the nose, slow and deep, with a relaxed diaphragm. Once someone masters that foundation, they can explore other techniques, but nasal breathing is the non-negotiable starting point.
Mouth Breathing's Hidden Damage: Teeth, Microbiome, and Systemic Health
McKeown is preparing a presentation for dentists in Boston and realized through deep research that he cannot understand how dentists missed mouth breathing's impact on oral health. When the mouth is open during breathing, moisture is lost through exhalation faster than saliva can replace it, drying the oral environment and changing the bacterial microbiome. This increases cavity and gum disease risk dramatically. McKeown cites a study from 1890 showing dentists already knew mouth breathing was the worst thing for cavities, yet the message vanished. Nestor adds that he found a cynical but plausible explanation: traditional dentists profit from drilling and filling cavities, so why would they educate patients on prevention that would eliminate their client base? Airway-focused dentists, by contrast, prioritize preventative health. The microbiome angle extends beyond teeth—bacteria translocate from mouth to gut, and researchers have detected Porphyromonas gingivalis in the brains of Alzheimer's patients, suggesting an oral-neurological pathway. Nestor emphasizes this isn't controversial science; it's all documented. The tragedy is that simple nasal breathing, proper tongue posture (tongue to roof of mouth during swallowing), and avoiding processed foods could prevent most orthodontic issues. Yet 50% of people wake with dry mouth, and most parents never learn this, meaning children grow up with preventable dental deformities.
Scoliosis, Structural Change, and Why Doctors Still Resist
Nestor's book includes the Katerina Shroth case: a woman with severe scoliosis who used breathing and stretching techniques to straighten her spine, then taught thousands of women with extreme scoliosis—cases hospitals said were incurable—to do the same. Pictures and videos document the results. Yet when Nestor presents this evidence to doctors, many insist it's impossible despite the photographs. One doctor with 30 years of research told Nestor, "Yeah, I saw the papers and pictures, but that's impossible." McKeown connects this to Andrew Wild's mentor's explanation: scoliosis develops from improper breathing during childhood when the body is developing rapidly. If one lung inflates more than the other due to poor posture and breathing habits, the spine grows asymmetrically. Therefore, correcting breathing and posture should theoretically prevent or correct curvature. McKeown notes this cannot be ethically proven with a controlled trial, but intuitively it makes perfect sense—the spine needs diaphragmatic stabilization and balanced lung inflation. Parents wanting healthy children should be interested in such non-invasive prevention, yet many lack the open-mindedness to look outside the conventional box. Both speakers note this resistance stems not from evidence but from institutional inertia and the collapse of outdated medical paradigms. The peanut allergy example illustrates the pattern: doctors once told parents to avoid peanuts, causing allergies to skyrocket; now they recommend introducing peanuts early. If that reversal happened, surely breathing's role in dental and spinal health deserves reconsideration.
Building Breathing Into Habit Rather Than Conscious Practice
Nestor emphasizes that his life isn't spent sitting around trying different breathing techniques; it's chaotic and stressful. The real benefit came from adopting better habits that took a few months to lock in. Once established, breathing becomes instinctive—he doesn't think about how to breathe anymore. He naturally adopts his breathing to whatever situation arises. In airports when late for flights, he consciously slows his breath to count of four in, four out through the nose. Previously he mouth-breathed constantly while jogging, surfing, and working. Now he never breathes through his mouth, and his body senses stress or environmental shifts and adapts automatically. He still accesses formal breathing practices—before going on stage in front of 2,000 people, he uses rapid Kundalini breathing to excite his sympathetic nervous system, proving to himself he can turn stress on and off intentionally. McKeown adds that converting to nasal breathing requires fewer boxes to check; once the habit is solid, natural sensitivity to environment takes over. Both agree the complexity is overstated. You breathe through the nose, you breathe slowly and deeply, you engage the diaphragm. That's the foundation. Everything else—hyperventilation, CO2 therapy, specific techniques—comes after mastery of the basics. The listener doesn't need to choose between their approaches; just start with nasal breathing and let curiosity guide what comes next.