When James Nestor published Breath: The New Science of a Lost Art, it became an instant classic — a deep dive into how modern humans have become the worst breathers in the animal kingdom, and what that means for our health. The book spent months on bestseller lists and has changed how millions of people think about every breath they take.
I’ve had the privilege of knowing James personally and professionally as we both work to advance understanding of the critical relationship between breathing, sleep, and health. Here are the key insights from our conversations and his groundbreaking research.
The Discovery That Changed Everything
James Nestor’s journey began with a Stanford University experiment where he and a colleague had their nostrils surgically blocked for 10 days, forcing exclusive mouth breathing. The results were alarming:
- Blood pressure increased significantly
- Heart rate elevated
- Sleep deteriorated dramatically — more awakenings, lighter sleep, and the onset of loud snoring
- Cognitive function declined
When the plugs were removed and they resumed nasal breathing, most metrics returned to normal within days. The experiment provided stark clinical evidence of what centuries of breathing practices had suggested: how you breathe fundamentally affects your health.
Key Takeaways From “Breath”
1. You’re Probably Breathing Too Much
Modern humans tend to overbreathe — taking in more air than our bodies need. This may seem counterintuitive, but chronic overbreathing actually reduces oxygen delivery to tissues by disrupting the balance of oxygen and carbon dioxide in the blood. The ideal breathing pattern is slow, nasal, and deep — about 5.5 breaths per minute.
2. Mouth Breathing Is Sabotaging Your Sleep
This is where breathing and sleep directly intersect. Mouth breathing during sleep contributes to snoring, obstructive sleep apnea, and poor sleep quality. The structural changes from chronic mouth breathing — narrowed dental arches, receding chins, and constricted airways — can develop from childhood and worsen over time.
3. Nasal Breathing Produces Nitric Oxide
One of the most remarkable findings in respiratory science is that nasal breathing produces nitric oxide (NO), a molecule that:
- Opens blood vessels and improves circulation
- Enhances oxygen uptake in the lungs by approximately 18%
- Kills bacteria and viruses
- Supports immune function
Mouth breathing produces virtually no nitric oxide. This alone should motivate anyone to prioritize nasal breathing.
4. Our Ancestors Breathed Better Than We Do
Nestor’s research into ancient skulls and breathing practices revealed that our ancestors had wider dental arches, straighter teeth, and larger airways. The shift to softer processed foods, less chewing, and more sedentary lifestyles has literally changed the shape of our faces and compromised our airways over generations.
5. Breathing Can Be Retrained
Perhaps the most hopeful finding: regardless of your current breathing patterns, you can retrain how you breathe. Techniques like:
- Buteyko breathing — reduces breathing volume to normalize CO2 levels
- Box breathing — equal inhale, hold, exhale, hold cycles
- Extended exhale breathing — activates the parasympathetic nervous system for relaxation
- Myofunctional therapy — strengthens tongue and throat muscles
What This Means for Your Sleep
The connection between breathing and sleep is direct and powerful. If you want to improve your sleep:
- Commit to nasal breathing — during the day and especially at night
- Address nasal obstruction — congestion, deviated septum, or allergies
- Practice slow breathing before bed to activate your relaxation response
- Read Breath — it will fundamentally change how you think about breathing
Your breath is the most accessible tool you have for improving your sleep and your health. Use it intentionally.
Learn more about James Nestor’s work at mrjamesnestor.com and explore his FAQ on breathing science.
By Nancy H. Rothstein, MBA, The Sleep Ambassador®