The Diary of a CEOThe Breathing Expert: Mouth Breathing Linked To ADHD, Diabetes & Child Sickness!
Steven Bartlett and James Nestor on how Modern Breathing Habits Quietly Destroy Health, Sleep, And Minds.
In this episode of The Diary of a CEO, featuring James Nestor and Steven Bartlett, The Breathing Expert: Mouth Breathing Linked To ADHD, Diabetes & Child Sickness! explores how Modern Breathing Habits Quietly Destroy Health, Sleep, And Minds James Nestor explains that most modern humans breathe dysfunctionally, and that this under‑appreciated habit underpins a huge range of illnesses from diabetes and asthma to anxiety, ADHD and chronic fatigue.
At a glance
WHAT IT’S REALLY ABOUT
How Modern Breathing Habits Quietly Destroy Health, Sleep, And Minds
- James Nestor explains that most modern humans breathe dysfunctionally, and that this under‑appreciated habit underpins a huge range of illnesses from diabetes and asthma to anxiety, ADHD and chronic fatigue.
- He describes how industrialized food, poor posture, mouth breathing, indoor air quality, and chronic stress have deformed our faces, shrunk our airways, and broken the ‘automatic’ breathing patterns evolution prepared us for.
- Through his own experiments, clinical research, and practical demonstrations, he shows how simple, free changes—especially nasal, slower, diaphragm-led breathing and better sleep breathing—can radically improve health, cognition, and emotional stability.
- Nestor argues that breathing should be treated as a core pillar of health, on par with diet, exercise and sleep, and that parents, doctors and educators are missing a huge lever by ignoring how children and adults actually breathe.
IDEAS WORTH REMEMBERING
5 ideasPrioritize nasal breathing—especially during sleep and exercise.
Breathing through the nose filters, warms and humidifies air, recaptures moisture, and boosts nitric oxide production up to sixfold, improving circulation and immune defense. Nestor’s Stanford experiment forcing 10 days of mouth breathing rapidly created snoring, sleep apnea, exhaustion and inflammation. Practical steps include consciously closing the mouth during the day, training to nasal-breathe while exercising (even if intensity must drop initially), and using gentle aids at night (e.g., Myotape, chin straps) to keep the mouth shut while maintaining safety.
Treat noisy or mouth breathing in children as a medical red flag, not a quirk.
If a child habitually breathes through an open mouth, snores, or if you can audibly hear them breathing at night, Nestor argues this is ‘cause for alarm’. Research on over 11,000 children found those with sleep-disordered breathing were 50–90% more likely to develop ADHD-like symptoms, hyperactivity, aggression, depression and anxiety. Many researchers he cites claim most so‑called ADHD in kids is sleep-disordered breathing. Parents should film their child sleeping, note mouth posture and sounds, and push pediatricians, ENTs and dentists to assess airway size, nasal obstruction, and breathing habits—not just prescribe stimulants or remove tonsils.
Rebuild functional breathing mechanics via posture and diaphragm training.
Most people use only ~5–10% of their diaphragm because they sit slumped and breathe shallowly into the upper chest. This forces the heart to work harder, limits gas exchange, and keeps the nervous system in a low-level stress state. Nestor demonstrates simple drills: sitting or standing tall with a relaxed but straight spine, placing hands above the hip bones and feeling them move laterally on inhale, then placing fingers on the upper chest to feel subtle expansion without lifting the shoulders. Practiced daily (and incorporated into workouts), this retrains the diaphragm, improves lung inflation, and supports better posture automatically.
Use simple breathing ratios to regulate stress and nervous system state.
Acute stress (email ‘apnea’, airport queues, arguments) pushes people into sympathetic over-breathing or breath-holding. Nestor suggests two main tools: (1) the ‘physiological sigh’—two quick inhales followed by a long, relaxed exhale—to rapidly reset breathing and calm a spike of stress, and (2) slow nasal breathing with a slightly longer exhale (e.g., 4 seconds in, 6 seconds out or about 5–6 seconds in and out) to strengthen parasympathetic tone, lower heart rate, and often reduce blood pressure by 10–15 points in minutes. The exhale lengthens heart-rate deceleration, signaling safety to the nervous system.
Monitor and build CO₂ tolerance instead of chronically over-breathing.
Chronic anxiety, panic, and ‘office stress breathing’ are strongly associated with low CO₂ levels from constant shallow, rapid breathing and frequent breath-holds. Nestor recommends a daily BOLT/control pause test: take a normal breath in, exhale to a neutral end, then hold until you first feel clear discomfort (swallow, diaphragm twitch, urge to breathe), and time it. Most people start around 15 seconds; athletes ~20; those with severe asthma/panic as low as 3–5 seconds. A functional target is ~40 seconds with a calm, unforced first inhale afterwards. Repeating this test and practicing slower nasal breathing and breath holds gradually increases CO₂ tolerance and resilience to stress.
WORDS WORTH SAVING
5 quotesYou can eat all the right foods, sleep eight hours a night, exercise all you want—if you are not breathing right, you will always be sick.
— James Nestor
What has changed is this modern environment is conspiring to make us sick.
— James Nestor
Some researchers said, ‘There is no such thing as ADHD. What that is, is sleep-disordered breathing.’
— James Nestor
The greatest indicator of lifespan was lung size and lung health.
— James Nestor
Look at a healthy infant sleeping. You can’t tell they’re breathing. That’s what healthy breathing is—it should not be perceptible.
— James Nestor
QUESTIONS ANSWERED IN THIS EPISODE
5 questionsFor parents who suspect their child has sleep-disordered breathing but whose pediatrician dismisses it, what specific data, videos, or measurements would you recommend they bring to force a more thorough airway and sleep evaluation?
James Nestor explains that most modern humans breathe dysfunctionally, and that this under‑appreciated habit underpins a huge range of illnesses from diabetes and asthma to anxiety, ADHD and chronic fatigue.
In adults already diagnosed with ADHD and on medication, how would you design a 90‑day breathing and sleep protocol to test whether their symptoms are significantly breathing-related—and what objective metrics (beyond ‘feeling better’) should they track?
He describes how industrialized food, poor posture, mouth breathing, indoor air quality, and chronic stress have deformed our faces, shrunk our airways, and broken the ‘automatic’ breathing patterns evolution prepared us for.
You argue that industrialized soft foods deformed our faces and airways within a generation; what would a realistic ‘re-chewing’ program for today’s toddlers and school kids look like without causing choking risks or family rebellion?
Through his own experiments, clinical research, and practical demonstrations, he shows how simple, free changes—especially nasal, slower, diaphragm-led breathing and better sleep breathing—can radically improve health, cognition, and emotional stability.
Given how dramatically indoor CO₂ impairs cognition, what practical ventilation or monitoring standards would you like to see mandated in offices, schools, and airplanes—and how should people advocate for these changes with employers or building managers right now?
Nestor argues that breathing should be treated as a core pillar of health, on par with diet, exercise and sleep, and that parents, doctors and educators are missing a huge lever by ignoring how children and adults actually breathe.
Many people find intense breathwork sessions (like holotropic breathing) emotionally overwhelming or destabilizing; what screening criteria and safety guidelines would you impose so that powerful breathwork is therapeutic rather than traumatic, especially for those with a history of mental health issues?
Chapter Breakdown
Breathing As The Missing Pillar Of Health
Nestor introduces the idea that dysfunctional breathing underlies many modern diseases and that most people are unaware of how badly they breathe. He recounts his own history with chronic respiratory issues and how a single breathwork class transformed his health and curiosity as a science journalist.
From Free-Diving Feats To Questioning Human Limits
Covering a free-diving championship in Greece showed Nestor that humans can do seemingly impossible things with a single breath. These feats convinced him that mainstream views of our physiological limits—and of breathing itself—are far too conservative.
How Modern Life Broke Our Breathing
The discussion shifts to how environmental and lifestyle changes have warped our facial structure, posture and automatic breathing patterns. Nestor argues that diseases like diabetes, asthma, autoimmune disorders and anxiety are deeply intertwined with dysfunctional breathing, especially at night.
The Stanford Mouth vs Nose Breathing Experiment
Nestor describes his self-experiment at Stanford comparing 10 days of enforced mouth breathing to 10 days of nasal breathing. The rapid deterioration in sleep, cognition and inflammation during the mouth-breathing phase gave objective data to back up traditional warnings.
How Widespread Is Dysfunctional Breathing?
Drawing on respiratory therapists and elite athletic trainers, Nestor estimates that the vast majority of people breathe poorly. He introduces the idea of a spectrum of dysfunction, from severe asthmatics to high-performing athletes who still have suboptimal patterns.
Industrial Food, Small Jaws, And Lost Ancestral Breathing
Nestor links industrialized food to drastic changes in human skulls: smaller jaws, crooked teeth, and narrower airways. He explains how reduced chewing and altered infant feeding practices have reshaped faces in just a few generations, making efficient breathing structurally harder.
Children, Sleep-Disordered Breathing, And ADHD
The conversation delves into the alarming prevalence of mouth breathing and poor sleep in children, and its strong association with behavioral diagnoses like ADHD. Nestor relays research suggesting many such cases are fundamentally breathing and sleep problems, not primary brain disorders.
Breathing, Lung Capacity, And Longevity
Nestor presents evidence that lung size and function are among the strongest predictors of lifespan. He explains how lung capacity declines with age but can be preserved or expanded through exercise and targeted breathing practices.
Practical Mechanics: Diaphragm, Posture, And Everyday Office Life
The discussion becomes hands-on as Nestor teaches how to feel proper diaphragmatic movement and shows how modern sitting compresses breathing. He suggests simple workplace adaptations like standing desks and walking breaks to restore natural breathing mechanics.
Nasal Breathing, Nitric Oxide, And Immune Defense
Nestor explains why the mouth is a backup breathing system and the nose is primary. He details the nose’s many functions—from moisture recapture to nitric oxide production—and introduces simple humming as a cheap immune-support tool.
CO₂, Indoor Air, Masks, And Hidden Cognitive Costs
The conversation turns to indoor air quality, COVID-era masking, and CO₂ as an overlooked indoor pollutant. Nestor demonstrates with a CO₂ meter how quickly levels rise in sealed rooms and cites compelling evidence that modest elevations impair cognition and health.
Stress, Anxiety, And Using Breath To Hack The Nervous System
Nestor connects everyday stress responses—like holding the breath over emails—to ancient threat responses, and shows how deliberate breathing can quickly shift us between sympathetic ‘fight or flight’ and parasympathetic ‘rest and digest’.
Diagnostic And Training Tool: The BOLT / Control Pause
Nestor teaches a specific breath-hold test (BOLT/control pause) that acts both as a diagnostic of respiratory and nervous system health and as a way to train CO₂ tolerance over time.
Asthma, Medication, And Reversing ‘Diseases Of Civilization’
Nestor challenges the assumption that asthma is an inborn, lifelong condition and shares how breathing retraining has dramatically improved or resolved asthma in many cases. He critiques purely pharmaceutical approaches that ignore underlying breathing behavior.
Transformational Breathwork: Holotropic Practices And Emotional Release
The host and Nestor discuss intense breathwork sessions (holotropic, Kundalini, pranayama) that can feel psychedelic and emotionally cathartic. Nestor differentiates their deliberate stress mechanism from foundational breathing habits and calls for more research on their brain effects.
Closing Reflections: Simplicity, Responsibility, And Accessible Tools
Nestor ends by reiterating that the most powerful breathing interventions are simple, free and available to everyone. He hints at his upcoming BBC Maestro course as a structured toolbox and emphasizes curiosity as his driving motivation.
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