Snoring, Sleep Apnea, Asthma, Crooked Teeth + More: The Dangers of Not Chewing + Breathing Correctly

Snoring, Sleep Apnea, Asthma, Crooked Teeth + More: The Dangers of Not Chewing + Breathing Correctly

In This Article

The Domino Effect of a Shrinking Skull

I was honored to interview James Nestor, author of the new New York Times bestselling book, Breath. This article is a review of my enlightening discussion with Nestor on our podcast—a must-watch interview.

Are Human Skulls Shrinking?

Sadly, it is true—modern skulls are much narrower than our ancestors’. Dating back 200 to thousands of years ago, a collection of skulls called the Morton Collection has documented a dramatic change in the structure of the human skull.

In Nestor’s new book, Breath, he spends years researching the causes and effects of this phenomenon. Our recent ancestors had much larger and bolder forward-facing jaws with wider mouths, expansive palates, larger airways, and nasal apertures twice the size of a modern human.1

With such a wide face, jaw, palate, and airways, breathing through the nose was effortless and obligatory. Our ancestors breathed through their noses and ate and spoke through their mouths, as we should be doing today.

The Shrinking Jaw

One explanation for this shift in our skulls is that our hunter-gatherer ancestors chewed some four to five hours a day, chomping on tough fibrous tubers, veggies, seed grasses, and meats. Chewing stress releases stem cells in the jaw and cranial bones that boost bone density, widen the jaw, and make us look and breathe better.2

The introduction of soft food, a trend away from nursing babies, and the forgotten wisdom of teaching children how to keep their mouths shut while they sleep has led to an epidemic of crooked teeth, breathing problems, unnecessarily pulling wisdom teeth and a litany of negative side effects associated with a lifetime of shallow upper-chest mouth breathing.

Negative Effects of Mouth Breathing1,4

  • snoring
  • sleep apnea (and all its related effects)
  • asthma
  • ADHD
  • migraines

Surprisingly, all collections of ancient skulls show larger airways, wider jaws, and straight teeth. Today, as a result of a diet of soft food, some 90% of the population have some sort of malocclusion, aka crooked teeth.3

Early orthodontists knew the mouths of babes were getting smaller—too small to fit all their teeth. Instead of pulling  wisdom teeth to make room, and bracing them into place as dentists and orthodontists do today, they devised oropharyngeal devices to widen the jaw and spread the palate open, so as to open the airways once again.

Today, this technique is called functional orthodontics and is making a resurgence. Parents are demanding better from their dentists and orthodontists by restoring oropharyngeal function, rather than just pulling and straightening teeth.

The Lost Palate

As jaws narrow and airways shrink, mouths are forced to open, allowing the tongue to fall into the lower palate to make room in the mouth for breathing. Without the tongue pressed up onto the soft palate (as happens with nose breathing), the soft palate narrows, airways narrow, and the palate becomes V-shaped, jamming the sinuses together instead of keeping them flat and wide. Use a clean thumb to see if your upper hard palate is an upside-down V-shape, U shape, or flat.

Normally, with nose breathing, the tongue is forced to the upper palate, and that keeps the palate wide and flat. Nursing and suckling have the same effect.  Both, along with chewing, keep the palate wide, which, in turn, keeps the airways large and open—one reason why nose breathing should be your preferred style.

As the face narrows and airways shrink, researchers find a strong link between chronic mouth breathing, snoring, sleep apnea, cognitive concerns, and breathing issues. Studies at Stanford University are starting to reproduce clinical findings that nose breathing during sleep can reverse and prevent sleep apnea.

Early Nose Breathing Research

In 1986, I started writing my book Body, Mind, and Sport on the benefits of nose-breathing exercise. In 1992, we did a study comparing nose and mouth breathing during exercise and later published that study in the International Journal of Neuroscience. Here is what we found:

We recommend "The Science Behind Why Nose Breathing is Better"

Benefits of Nose-Breathing Exercise (as Compared to Mouth-Breathing Exercise)5,6

  1. Improved lower lung gas exchange
  2. Improved brainwave coherence
  3. Increased alpha wave activity
  4. Decreased perceived exertion or stress during exercise
  5. Increased endurance
  6. Increased parasympathetic activity
  7. Lower and more efficient breathing rates
  8. Nose breathing may reduce stress, and thus deliver numerous health benefits linked to increased parasympathetic activity

Many other profound health-promoting pathways from nose breathing are being discovered, and there are possibly even more on the horizon as more studies are done!

Benefits of Nose Breathing

  1. Nose breathing boosts nitric oxide. Nitric oxide is a powerful immune-boosting molecule produced in the sinuses during nose (not mouth) breathing. Discovery of this molecule earned the Nobel Prize in Chemistry as a result of its important health benefits.8
  2. Nose breathing activates the vagus nerve, which triggers the rest, digest, and destress nervous system response.1,2 The vagus nerve is also the main pathway used by the gut-brain axis, linking the microbiome with brain, mood, and cognitive function.7
  3. Deep nose breathing that activates the parasympathetic nervous system also stimulates baroreflexes in blood vessels mediated through emotional centers in the brain. For example, your blood pressure will go up when you are under emotional stress. This effect not only supports healthy blood pressure, but is also linked to emotional resiliency and mood stability.7

Relearning How to Nose Breathe

The best ways to start the process of relearning how to nose breath is by:

  1. Nose breathe during exercise.
  2. Sleep with mouth closed.
  3. Slow breathe, at a rate of six breaths per minute.
  4. Stop overbreathing.
  5. Practice pratiloma, an Ayurvedic breathing technique to strengthen the diaphragm.

What do you think about the changes in the human skull, specifically the shrinking of the jaw, palate, and nasal cavities? What are you doing to ensure that you can breathe optimally?

Want to win a copy of Breath by James Nestor and Body, Mind, and Sport by John Douillard? Enter here.

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Dr. John

14 thoughts on “Snoring, Sleep Apnea, Asthma, Crooked Teeth + More: The Dangers of Not Chewing + Breathing Correctly”

  1. hello john,

    i so appreciate your interview with james nestor. i watched it and i have also read his book “Breath”and loved it. i have an interesting story about the too small mouth that we seem to all have. back in 1966 i was just beginning to study nutrition. both of my sisters and myself had the canine teeth that didn’t fit in our mouths. my older sister had the teeth behind the canines, pulled and the canines moved into place on their own after that. i only had the issue on one side and we did nothing about it and i still have it. my younger sister who was 12 had the canines protruding on both sides. back to my study of nutrition. i read that if you gave a child large doses of vit. A and vit, D, three times a week that the palate would spread. they said that it had to be done before age 12. but we tried it anyway and my sisters teeth straightened out. it took a year. so nutrition plays a big part in the small mouth issue as well.

    i find this all so fascinating and am glad that we are all becoming aware of information that has been around for a long time.

    thank you so much, venice

    • Hi Ivo,

      Yes good point which is why I have written about potential deficiencies in a vegetarian or vegan diet.

      Choosing to get those nutrients with supplements and then be able to healthfully be a vegetarian and do no harm, is a choice that is extremely hard to argue with.

      Be Well,
      Dr. John

  2. My husband was recently diagnosed with parotid gland cancer. He also was recently diagnosed with a significant tongue tie. He is 71 years old. He in not overweight and sleeps with a cpap. We think the tongue tie could have contributed to or even caused the cancer. He also has used a cell phone quite a bit on the side of his face with the cancer.

  3. I just completed an orthodontic reversal and dental implants to replace the permanent teeth that were “stolen” from me after two rounds of 80’s era extract and retract orthodontics. I had horrible allergies as a child that caused mouth breathing and inward collapse of both dental arches. Instead of expanding to create a bigger structure, they kept pulling teeth that would no longer “fit” in my small mouth. My maxilla ended up pulled 1 cm inward which locked my mandible back to cause airway restriction, TMJ, and daytime exhaustion. I will never have a click-free jaw but I am no longer quietly suffocating in my sleep and I have the space in my mouth for proper tongue resting posture. A check-in with a functional orthodontist with young children (like <5 ideally) can indicate if they are on track to downward instead of forward facial growth and address the problem before they become a cautionary tale like me.

  4. As a sufferer of sleep apnea (at 5’1″ and 110 Lbs), a yogi, a meditator and with a pranayama practice, sleep is still illusive as the structural damage perhaps has been done. I wish there was a cure. Breathing and an oral appliance so far have not helped much, but hopefully it has for others. Thank you for keeping this on the forefront, Dr. John!

  5. Thank you so interesting really appreciate article.
    After WWII UK hardly any adult in my family had their own teeth.
    No food bombing London. Bombs fell a mile from Mum giving birth to me in a strangers house
    I ended up with being bullied and called goofy as my teeth in front stuck out.
    Guys Hospital was where my Gran took me no Dentists terrifying surrounded by men in training peering at me I was 11.
    I was told too small mouth and they yanked teeth out. All my life spent a fortune pain suffering
    after terrible Dental on going work I have ended up with Tinnuitis non stop and TMJ .
    Dentist want $25,000 more root canals , drilling or $30.000.00 to take out.
    I am healthy except for above but in pain and terrified what to do. I can hardly open my mouth to eat

  6. hello john,

    in respones to your asking about where i got my information on the vit.A and vit.D to widen my sisters palate: the book was “Lets Have Healthy Children” written by Adele Davis in 1951. of course so much more has been discovered since her books were written, but she had some helpful ideas in a time when most of people had no idea about nutrition.

    Venice Kelly

    • Hello Venice,

      Thank you, I would love to see if there was a study associated with that and whether A and D are needed for full development of the palate rather than widen one already with closed growth plates.

      Be Well,
      Dr. John

  7. As an otolaryngologist with 31 years experience, I wholeheartedly recommend a checkup by an otolaryngologist for any child who is a mouthbreather, as early as possible. A two year old with his mouth hanging open all the time is destined for major othodontic trouble. Often a simple adeenoidectomy can make all the difference. Others may need enlarged tonsils removed as well, or allergy treatment. The transformation is often dramatic, including better sleep and speech.

  8. In trying nose breathing while exercising, I can only do it a rapid rate. How do I train myself to get to 14 breaths a minute at 200 watts as your cyclists did? Is there a protocol that will let me get there over time? Thanks, John

  9. This is very useful information. Weston Price’s book “Nutrition and Physical Degeneration: A Comparison of Primitive and Modern Diets and Their Effects” extensively looks at the links between nutrition and not only mouth width, but also chest and hip width as well.


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