I've been interested in it for the last 2 or 3 years, and pleasantly surprised that it's showing up on HN a lot.
Here's a surprising claim that has scientific concensus: Basically ALL humans have problems breathing. That is, apes and other mammals don't have these problems.
The two main reasons are the anatomical changes due to the evolution of speech, and the advent of agriculture, which completely changed our diets and thus the structure of our jaw.
The book is very good, but it's not "conclusive". It's a good exploration of many facets of breathing. It is a big subject and everyone is a little different.
However it's been eye opening to me how many "minor" unexplained chronic health problems are ultimately caused by bad breathing. (And these turn into major problems over 10 or 20 years.) If you go to the doctor, you'll get treatment for the symptoms and not the cause (this has happened to many people in my family, and many people I know)
I would say the best popular/scientific books are Breath by Nestor (released this year), and Jaws by Kahn (2018). It's coming into public consciousness, although the books show that this knowledge was available in the 1930's and forgotten, and in the 1700's and forgotten, etc.
The shorter clips extracted from this interview are compelling.
For more specific medical advice, there is "Sleep, Interrupted" by Park, and "The 8 hour sleep paradox" by Burhenne.
It's a big area because breath affects so many parts of your physiology, but all these people are saying overlapping things, coming from their own professional viewpoint. There is a particular focus on the relation to teeth, and that is one of the most common correlations.
But there are also correlations with sinus problems, acid reflux, anxiety, ADD, high blood pressure, weight gain and obesity, and bad sleep. That is, extremely common things that most people just live with for years. But they don't have to.
Also, if you have children, you have to answer the question: why do so many children need orthodontic work? What happened 1000 years ago when there were no orthodontists?
The answer is that our diets changed drastically in the last 200 years, and also ~10,000 years ago with the advent of agriculture. If you don't believe that, the question still needs an answer!
Same with the causes of all these minor chronic problems. Most people just live with the symptoms, and for some reason don't ask for the fundamental reasons why. Like food, breath is at the the base of your physiology, so it makes sense as a candidate.
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If you want a whole bunch of studies, I have this book (recommended by my dentist) and there are 140 scientific papers cited in the back.
"Airway dentistry" is actually its own separate subfield, which is weird because a lot of practicing dentists seem only dimly aware of it! But at least in the United States you can find "sleep dentists" or "airway dentists" in most major cities. But somehow I went 20+ years being completely unaware of their existence.
The evidence that's cited over and over for the agriculture thesis is the collection of skulls at U Penn. Modern humans have drastically different skulls than humans before agriculture. That is described in "Breath" and "Jaws".
I don't recall a primary source for the speech thesis, but it's mentioned in "Sleep, Interrupted", "Jaws", and "Breath". Although actually I just googled and it was easy to find a reference:
Significant evolutionary changes to the human head are flat face, smaller chin, shorter oral cavity, changes in jaw function, repositioning of ears behind jaws, ascent of the uvula and descent of the epiglottis, right angle bend in tongue, creation of compliant, combined, flexible airway-foodway, and speech.9
Anyway I think there is plenty of scientific evidence. What really matters is that this knowledge makes its way into popular culture and common medical practice. That appears to be happening, but it's surprisingly uneven!
Hope that helps, and feel free to follow up with questions... I'm thinking of starting a blog on this subject, based on reading several books, and talking to many doctors who seem completely unaware of this.
Nestor's book explains why doctors are unaware of it, and why most people get poor treatment for these issues: because doctors are specialists, and they are used to fixing severe problems. They are trained to see their part of the equation. Breathing is more holistic because it affects everything: your teeth, mouth, eyes, brain, heart, etc. And bad breathing kills you over 20 years. It doesn't cause an emergency in most cases.
What do we know about the area behind the nose? Is that the sinuses? Is the book “Jaws” discussing the sinuses? It sounds to me like Jaws is about the mouth area, not the areas behind the nose.
But, thank you a lot for these resources, I am excited to learn about this topic as I see it affects my (and others) life a lot
All those books definitely talk to some degree about those areas. I forget which ones, but they say the anatomy of the maxilla (the upper jawbone which forms the nose) is key to breathing. And dentists talk about a "constricted arch" which I think is a related issue. I don't think I have these issues so I didn't pay particular attention there.
The way I think about it is that breathing is a big geometry problem, and everyone is a little different, and every medical provider has their own viewpoint, and set of solutions they can apply. For example I don't think Nestor has the same problems that I have. He talks about his problems in the YouTube video and in the book.
So you will probably have to look around a lot. It's a big topic. But the common point is that almost all humans have problems breathing, but it manifests in different ways depending on the unique geometry of their head.
It's kind of like if you crushed 100 pumpkins, not all of them are going to be crushed in the same way, but they'll all have some problem ...
And it depends on medical history -- a lot of people seem to have bad breathing because of childhood orthodontic work.
When I was a young girl I had orthodontic extractions and wore a cervical headgear that pulled my upper jaw back and made my oral cavity much smaller than nature intended it to be. Before this treatment, I was a fit and healthy child who had no problems sleeping and waking up. After extractions and headgear, part of my vitality went away and I lived a life of constant fatigue, plagued with fainting spells and low energy for more than twenty years
Feel free to reach out by e-mail if you learn anything interesting about your case!
Babies have drastically different skulls, but there are infants who snore. My understanding is that this is increasingly common (if you ask doctors), and it's caused by the same anatomical problems that cause sleep apnea in adults.
People used to think snoring is benign, but others will say that infants should never snore.
The common adenoids surgery in children is also due to a small airway, although people will tell you it's because they have "large adenoids"!
Your second sentence doesn't follow. Babies exhibit fewer of these problems, but that doesn't mean that evolutionary changes and agriculture aren't the cause of the problem in adults. Babies don't have developed jaws, and one of the main points is that jaw development isn't primarily genetic; it's shaped by the "environment" of the jaw, which is essentially the diet.
If braces can shape the jaw, then so can 10 years of eating soft foods, industrial cooking, etc.
Breathing is such an interesting aspect of life that we don’t explore a lot in popular culture.