The Rich Roll Podcast

Episode: The New Science Of Breath: James Nestor On Why Most People Are Breathing Wrong

Date: February 2, 2026
Host: Rich Roll
Guest: James Nestor (NYT Bestselling Author, "Breath")

Overview

This episode dives deep into the often-overlooked topic of how modern humans, especially in industrialized societies, are breathing incorrectly—primarily mouth breathing instead of nasal breathing—and the profound impacts this has on everything from sleep and mental health to athletic performance and childhood development. Rich Roll speaks with James Nestor, whose research and bestselling book "Breath" have been pivotal in popularizing the science of breath. Together, they explore historical, biological, and practical dimensions of breathing, and provide actionable steps for improving breath for better well-being.

Key Discussion Points & Insights

1. Dysfunctional Breathing: A Modern Epidemic

• [00:01-01:29] Nestor opens with the claim that "most of us... are doing it in a dysfunctional way."
  • Dysfunctional breathing is likened to eating ultra-processed junk food—survivable, but not healthy.
• [01:29-07:19] Industrialization has led to a cascade of problems:
  • Small mouths, crowded/crooked teeth (malocclusion), and increasingly prevalent mouth breathing.
  • Ancient humans had wide jaws and straight teeth; modern diets and weaning habits do not require prolonged chewing, impeding proper jaw/airway development.

Quote:

"Just like you could survive eating Dunkin Donuts all day long. You survive. Doesn't mean you're healthy."
— James Nestor [11:36]

2. Structural and Dietary Origins of Poor Breathing

• [07:53-10:48]
  • The consistency of food and a lack of chewing in childhood leads to underdeveloped jaws and airways.
  • Baby-led weaning and harder foods help develop mouth and airway structures.

Quote:

"Our ancestors were chewing for around two to three hours a day... the mouth widens. Right. So it has this input, this exercise."
— James Nestor [08:03]

3. Physiological Consequences of Mouth Breathing

• [11:21-17:58]
  • Mouth breathing leads to shallow, chest-dominant breaths, not efficiently oxygenating the body.
  • Increases cavity risk, leads to a more acidic mouth environment, and perpetuates a cycle of stress by chronic activation of the sympathetic nervous system.
  • Shallow "over-breathing" reduces carbon dioxide (CO2), which paradoxically impairs oxygen delivery to cells.

Quote:

"The faster and more shallow you breathe... all those messages from your lungs go to your brain to tell you it's an emergency, that you need to panic."
— James Nestor [12:14]

4. The Critical Role of Nasal Breathing

• [17:06-19:15]
  • Nasal breathing humidifies, filters, and regulates airflow, optimizing nervous system and CO2/O2 balance.
  • Slow, deep nasal breaths favor parasympathetic (rest and digest) nervous system and improve overall physiology.

Quote:

"The foundation of healthy breathing is what you're doing unconsciously."
— James Nestor [17:58]

5. Lifestyle Factors: Posture & Sedentary Behavior

• [18:40-20:28]
  • Sitting hunched over impedes diaphragmatic breathing.
  • Training the body for better posture and breath awareness is essential but requires habit formation rather than constant conscious effort.

6. Sleep, Air Quality, and Chronic Illness

• [27:04-36:04]
  • Poor indoor air quality (high CO2 environments) can diminish cognition and aggravate stress.
  • Most people are "recycling" poor-quality indoor air in schools, hotels, and offices, negatively affecting health and performance.
  • Sleep-disordered breathing and sleep apnea are linked to hypertension, heart disease, diabetes, and impaired childhood development.
  • Measurement and optimization of air quality and breathing during sleep are both practical first steps.

Quote:

"Around one in every 25 breaths you are taking in these hotels is someone else's exhalation."
— James Nestor [27:31]

7. Breathwork and Physical/Mental Performance

• [41:14-47:32]
  • Trained breathers (like freedivers) develop enormous CO2 tolerance; this skill helps not just in athletics, but in anxiety and asthma management.
  • Breathwork (especially nasal, slow, and diaphragmatic) holds powerful potential for symptoms of anxiety, ADHD, and more.

Quote:

"Once you do that, you can not only hold your breath... but it's extremely effective for people with anxiety and for people with asthma and even people with some forms of COPD."
— James Nestor [42:54]

8. Chronic Disease, Sleep, and ADHD

• [43:40-67:37]
  • Sleep-disordered breathing is a significant, underdiagnosed cause of ADHD symptoms and other neurodevelopmental or behavioral issues in children.
  • Removing tonsils/adenoids often resolves symptoms—implying the root cause is physical, not strictly neurological.

Quote:

"Around 70 to 80% of kids with ADHD suffer from sleep disorder breathing... Over 50% of kids that had these surgeries to clear their airways, their symptoms of ADHD disappeared."
— James Nestor [64:04]

9. Practical Techniques and Interventions

• Daily Nasal Breathing Training:

  • Use mouth tape or conscious exercises to train the body to nasal breathe day and night, starting with short bouts.
  • Snoring/sleep breathing can be tracked with apps like SnoreLab.

• Diaphragmatic Breathing Drills:

  • Hand on chest and hand on belly; focus breath movement into lower hand.

• CO2 Tolerance Testing ("BOLT" or Brian McKenzie Test):

  • Take a maximal inhale, then time a slow exhale through pursed lips. 60-90 seconds is optimal CO2 tolerance.

Quotes:

"You have to become an obligate nasal breather, especially at night, but in the day as well."
— James Nestor [75:35]

"I have so much trouble sleeping without [mouth tape]."
— James Nestor [73:55]

10. Breathwork Modalities: Benefits & Cautions

• Extreme forms such as Wim Hof and holotropic breathing create hormetic stress, useful for nervous system "reset"—but the foundation must be normal, healthy breathing first.

"Unless you are able to be a normal breather first, then I would not bother with any of those other things." — James Nestor [82:13]

11. Athletic and Longevity Implications

• Lung function is a potent predictor of longevity (Framingham Heart Study).
• For athletes, developing greater lung capacity and raising CO2 tolerance is a performance multiplier, especially in endurance sports.

"The sooner you lose your lung function... the sooner you're going to die."
— James Nestor [100:34]

12. Cultural, Spiritual, and Mystical Traditions

• Pranayama in yoga and breathwork in qigong/chigong both reflect the ancient recognition of "life force" energy (prana/chi) as accessed and modulated via breath.

"I found that almost all of them were saying the same thing in different ways. The breath work modalities were so similar."
— James Nestor [92:22]

Notable Experiments & Research

The Stanford Mouth Breathing Experiment

[57:29-61:43]

• Nestor and a colleague underwent 10 days forced mouth breathing, then 10 days nasal.
• Results:
  • Snoring increased 1300% within 24 hours.
  • Both developed sleep apnea.
  • Blood pressure spiked.
  • All negative effects reversed within 2 days of returning to nasal breathing.

"Within days, your blood pressure spiked 13 points into stage one hypertension. Your HRV plummeted... Immediate recovery from all of these when you start breathing through the nose."
— Rich Roll summarizing James Nestor's findings [60:30]

Actionable Takeaways

For Immediate Implementation

1. Track your sleep breathing using SnoreLab or SnoreClock.
   [131:32]
2. Practice nasal breathing throughout the day. Use mouth tape if needed, but acclimate gradually.
3. Employ the "hand on belly, hand on chest" drill to ensure diaphragmatic breathing.
4. Perform regular CO2 tolerance tests to track progress.
5. Chew more, especially for kids developing jaw structure.
6. Address structural issues (deviated septum, inflamed tonsils) if they impede nasal airflow—seek expert help.

Memorable Quotes & Moments

• On Overbreathing:
  "This perpetual vicious cycle of over breathing is not only inefficient, but it's denying you of easy access to oxygen to fuel your cells."
  —James Nestor [15:28]

• On Sleep & ADHD:
  "If you look at someone with asthma... who figured out a way of breathing better, specifically slowly and through the nose, who no longer have any symptoms of asthma."
  —James Nestor [45:27]

• On Industrialized Food:
  "The moment industrialized food comes into a culture, 50% of the next generation will have a small mouth and crooked teeth."
  —James Nestor [06:15]

• On Behavioral Change:
  "It's so unsexy getting normal breathing down when you could be hanging out... at some illustrious retreat doing breathwork. That's so hot. But it's not going to do you much good if you can't breathe normally." —James Nestor [82:43]

Timestamps for Important Segments

• 00:01 – Dysfunctional breathing as a modern norm.
• 02:28 – How industrialization changed jaw/mouth structure.
• 08:03 – The impact of soft foods and lack of chewing.
• 13:16 – Link between mouth breathing and chronic stress.
• 17:06 – Why nasal breathing matters.
• 27:04 – Poor air quality and how it affects health.
• 36:04 – "Green" buildings and air recycling.
• 41:14 – Breathwork & CO2 tolerance.
• 57:29 – The Stanford mouth breathing experiment.
• 64:04 – ADHD, sleep disordered breathing, and the impact on children.
• 75:35 – Starting a formal breath practice.
• 100:34 – Lung function as a lifespan predictor.
• 131:32 – How to start: tracking, nasal breathing, CO2 tolerance.
• 133:08 – CO2 tolerance/slow exhale test in practice.

Resources & References

• Breath by James Nestor
• SnoreLab/SnoreClock apps (sleep breathing tracking)
• Buteyko breathing method (CO2 tolerance training)

Final Thought

James Nestor advocates that learning to breathe properly—primarily through your nose, low and slow—offers tangible improvements in health, cognition, performance, and emotional well-being. It’s a foundational, overlooked pillar of health, available to everyone, at any age, for free.

“These breathwork practices are so incredibly powerful and it's extremely simple. This is why people think it's not going to work.”
— James Nestor [16:09; closing summary]