Book Review: Breath
Open your eyes to opening your nose
I kept coming across people talking about breathing, and breathwork, and this idea that you should tape your mouth closed at night to breathe through your nostrils. I finally saw enough references to this that I decided to just read the book — Breath, by James Nestor.
Can any of this be trusted?
At times reading this book I wished it had been written by someone who was a little more critical. I would've liked Breath better if it was a little more Good to Go by Christie Aschwanden, and a little less Natural Born Heroes by Christopher McDougall. I guess that won't make sense to anyone who hasn't read those books...Good to Go, in my opinion, does a great job of understanding what separates good and bad science, good and bad studies, and is never overly wowed by any one study. Natural Born Heroes is at the other end of the spectrum—an interesting book about exercise, but it borders on claiming there is ancient magical out there for us to take advantage of.
In the Epilogue, which he uses as a summary of the book, he makes this comment:
The few gasping breaths Stephen Curry takes before dunking a basketball, or a sick kid huffs when he has a fever, or you take in when you’re laughing with your friends—this temporary mouthbreathing will have no long-term effects on health.
What does this have to do with whether I can trust the author? Well, any basketball fan will know that Steph Curry is known for just about anything but his ability to dunk a basketball. ("Steph Curry’s dunks account for just .003% of his overall field-goal attempts." says the first source I clicked on.) The imagery is useless—because not even the basketball fans out there have a mental picture of what Steph looks like when he dunks. (Steph's also known for being one of the best-conditioned players in the league, making it even less likely anyone has a mental image of him gasping before a dunk.)
This sentence strengthened my feeling that the author isn't exactly world-class at knowing what he doesn't know. After reading the book, I'm definitely intrigued, but still skeptical. (On the other hand, a full 30% of the book is taken up by the Notes section. So he's certainly giving the impression of striving for scientific accuracy.)
I'm buying some of it, but I think we should doubt that breathing has magic-level powers. A story like this one, for example, is a little tough to believe:
In 2015, researchers at the University of California, San Diego, recorded the breathing patterns of a schizophrenic woman over the course of three consecutive years and found that she had a “significantly greater” left-nostril dominance. This breathing habit, they hypothesized, was likely overstimulating the right-side “creative part” of her brain, and as a result prodding her imagination to run amok. Over several sessions, the researchers taught her to breathe through her opposite, “logical” nostril, and she experienced far fewer hallucinations.
But I hope this book helps stimulate more research in the area, so we can better separate fact from fantasy. Here was one other passage I highlighted as being pseudo-scientific:
For every ten pounds of fat lost in our bodies, eight and a half pounds of it comes out through the lungs; most of it is carbon dioxide mixed with a bit of water vapor. The rest is sweated or urinated out. This is a fact that most doctors, nutritionists, and other medical professionals have historically gotten wrong. The lungs are the weight-regulating system of the body.
He's right (as far as I'm aware) that we mostly exhale out things like fat that were once solid in our bodies. But that shouldn't lead someone to immediately claim the lungs are the weight-regulating system of the body.
Strong jaws and nose breathing
On to the actual arguments of the book. To me, the best (and most likely to be true) ideas in the book are his most basic arguments.
First, he argues that the softness of our modern diet has changed the shape of our heads in a way that negatively affects our breathing:
Forty percent of today’s population suffers from chronic nasal obstruction, and around half of us are habitual mouthbreathers, with females and children suffering the most. The causes are many: dry air to stress, inflammation to allergies, pollution to pharmaceuticals. But much of the blame, I’ll soon learn, can be placed on the ever-shrinking real estate in the front of the human skull...
“Since we have known for a long time that savages have excellent teeth and that civilized men have terrible teeth, it seems to me that we have been extraordinarily stupid in concentrating all of our attention upon the task of finding out why all our teeth are so poor, without ever bothering to learn why the savage’s teeth are good,” wrote Earnest Hooton, a Harvard anthropologist... [this person lived a long time ago, sorry about the language —LT]
They had expansive sinus cavities and broad mouths. And, bizarrely, even though none of the ancient people ever flossed, or brushed, or saw a dentist, they all had straight teeth. ..
Our ancient ancestors chewed for hours a day, every day. And because they chewed so much, their mouths, teeth, throats, and faces grew to be wide and strong and pronounced. ..
When mouths don’t grow wide enough, the roof of the mouth tends to rise up instead of out, forming what’s called a V-shape or high-arched palate. The upward growth impedes the development of the nasal cavity, shrinking it and disrupting the delicate structures in the nose. ..
Over the next few centuries, food would become more and more refined...All these methods extended the shelf life of foods and made them more accessible to the public. But they also made foods mushy and soft.
Surprisingly to me, especially since he argues that "soft" foods are a problem, he also says breastfeeding is good for babies' facial structure:
The chewing and sucking stress required for breastfeeding exercises the masseter and other facial muscles and stimulates more stem cell growth, stronger bones, and more pronounced airways. Until a few hundred years ago, mothers would breastfeed infants up to two to four years of age, and sometimes to adolescence. The more time infants spent chewing and sucking, the more developed their faces and airways would become, and the better they’d breathe later in life. Dozens of studies in the past two decades have supported this claim.
The author wears a retainer meant to promote widening and bone growth in the face, and sees impressive results:
I visited a private radiology clinic in downtown San Francisco and had my airways, sinuses, and mouth rescanned...
The results were stunning. I had gained 1,658 cubic millimeters of new bone in my cheeks and right eye socket, the equivalent volume of five pennies. I’d also added 118 cubic millimeters of bone along my nose, and 178 along my upper jaw. My jaw position became better aligned and balanced. My airways widened and became firmer.
If you don't want to get a special retainer, there are lots of "jawline exercisers" available on Amazon. I guess that's a better name for it than "adult human chew toy". The author also suggests chewing gum for hours at a time. Should I have chewed more gum as a kid? I always assumed it was unhealthy...
(To his credit, Nestor also suggests just eating more hard, chewy food.)
In summary, humans began eating softer foods, which meant our facial bones and muscles didn't get worked out enough, and as a result the structure of our faces changed. Specifically, our mouths didn't grow as wide as they should and pushed upwards instead, making our nasal passages smaller.
The next facet of the argument is: this is bad because breathing through our noses is good for us. Here's what the book says about that. The wisdom of the ancients, according to the author, is unanimous in favor of nose breathing:
Around 1500 BCE, the Ebers Papyrus, one of the oldest medical texts ever discovered, offered a description of how nostrils were supposed to feed air to the heart and lungs, not the mouth. A thousand years later, Genesis 2:7 described how “the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul.” A Chinese Taoist text from the eighth century AD noted that the nose was the “heavenly door,” and that breath must be taken in through it. “Never do otherwise,” the text warned, “for breath would be in danger and illness would set in.”
Of course we shouldn't just rely on what ancient civilizations believed. Here's the scientific explanation, in short:
Working together, the different areas of the [nose] will heat, clean, slow, and pressurize air so that the lungs can extract more oxygen with each breath...
Dr. Mark Burhenne had been studying the links between mouthbreathing and sleep for decades, and had written a book on the subject. He told me that mouthbreathing contributed to periodontal disease and bad breath, and was the number one cause of cavities, even more damaging than sugar consumption, bad diet, or poor hygiene. (This belief had been echoed by other dentists for a hundred years...) Burhenne also found that mouthbreathing was both a cause of and a contributor to snoring and sleep apnea. He recommended his patients tape their mouths shut at night.
“The health benefits of nose breathing are undeniable,” he told me. One of the many benefits is that the sinuses release a huge boost of nitric oxide, a molecule that plays an essential role in increasing circulation and delivering oxygen into cells…
Nasal breathing alone can boost nitric oxide sixfold, which is one of the reasons we can absorb about 18 percent more oxygen than by just breathing through the mouth...
The whole thing seemed a little sketchy until Ann Kearney, a doctor of speech-language pathology at the Stanford Voice and Swallowing Center, told me the same. Kearney helped rehabilitate patients who had swallowing and breathing disorders. She swore by mouth taping.
Even Healthline.com has a straightforward article on the benefits of nasal breathing, so perhaps this is more widely accepted than I'd realized. I brought up the book Good to Go earlier to contrast with the bordering-on-pseudoscience feeling I got from Breath, but here's one thing that reflects positively on Breath: perhaps the biggest takeaway from Good to Go is that good sleep is critical for athletes. Even if all this other stuff about breathing is completely bunk (which I don't think it is!), nasal breathing helps people sleep better, and for that alone it's a powerful and worthwhile technique.
Although I'm generally convinced, there were sections too where even the claims about nasal breathing strained my belief, like this study the author shares comparing mouth and nasal breathing:
...By the time athletes reached the hardest stage of the test, pedaling out 200 watts of power, they were panting and struggling to catch a breath.
Then Douillard repeated the test while the athletes breathed through their noses. As the intensity of exercise increased during this phase, the rate of breathing decreased. At the final, 200-watt stage, one subject who had been mouthbreathing at a rate of 47 breaths per minute was nasal breathing at a rate of 14 breaths a minute. He maintained the same heart rate at which he’d started the test, even though the intensity of the exercise had increased tenfold.
Another argument that strains my belief is that a lack of nose breathing is...the reason that people slouch?
Many of us adopted this S-posture [i.e., slouching] not because of laziness but because our tongues don’t fit properly in our too-small mouths. Having nowhere else to go, the tongue falls back into the throat, creating a mild suffocation. At night, we choke and cough, attempting to push air in and out of this obstructed airway. This, of course, is sleep apnea, and a quarter of Americans suffer from it.
By day, we unconsciously attempt to open our obstructed airways by sloping our shoulders, craning our necks forward, and tilting our heads up.
There's a chance this is true, to be sure. But I would be happy to bet against it.
Breathing...less? And other wild breath ideas
Another idea that I couldn't bring myself to believe is that we breathe too much:
The key to optimum breathing, and all the health, endurance, and longevity benefits that come with it, is to practice fewer inhales and exhales in a smaller volume. To breathe, but to breathe less...
Buteyko and his methods have been largely dismissed by today’s medical community as pseudoscience. Nonetheless, a few dozen researchers over the past few decades have attempted to gain some kind of real scientific validation on the restorative effects of breathing less. One study at the Mater Hospital in Brisbane, Australia, found that when asthmatic adults followed Buteyko’s methods and decreased their air intake by a third, symptoms of breathlessness reduced by 70 percent and the need for reliever medication decreased by around 90 percent. A half-dozen other clinical trials showed similar results...Still, nobody seems to know exactly why breathing less has been so effective in treating asthma and other respiratory conditions.
Nestor doesn't explain why we all started breathing more (at least not as well as he explains why we stopped nasal breathing). The most reasonable explanation, to me, would be that it's easier to take big breaths with the mouth than the nose, so the same changes that caused us to stop nasal breathing also made us breathe too much.
But breathing too much feels pretty questionable to me. People eat more than they used to, but that's (partly) because we've engineered super-palatable foods in the past 100+ years. We haven't engineered super-palatable air, though. One of those "wisdom of the ancients" ideas that's floating around our modern culture is that we should trust our body, and listen to our body. This book seems to be saying the exact opposite—that we can't even trust our bodies to breathe the right amount, we have to intentionally breathe less. I'm not quite ready to buy it.
Of course Wim Hof makes an appearance towards the end of the book. This story is a bit hard to believe as well:
In 2011, researchers at Radboud University Medical Center in the Netherlands brought Hof into a laboratory and started poking and prodding him, trying to figure out how he did what he did. At one point, they injected his arm with an endotoxin, a component of E. coli. Exposure to the bacteria usually induces vomiting, headaches, fever, and other flu-like symptoms. Hof took the E. coli into his veins and then breathed a few dozen Tummo breaths, willing his body to fight it off. He showed no sign of fever, no nausea. A few minutes later, he rose from the chair and got a cup of coffee.
Then there's this yogi, Swami Rama:
In another experiment at the Menninger Foundation, he voluntarily stopped his heart from pumping blood for 17 seconds. He did this by increasing his heart rate to 300 beats per minute so that the ventricles stopped pumping and the atria just fluttered. He was further seen to create a temperature differential of 5 degrees Celsius between two areas on the palm of his right hand. (quoted from Wikipedia)
But if this is something people can really do...why is the best example we have from the early 1970s?
I already knew about using breathwork to induce hallucinations, from reading the book How To Change Your Mind. Between that book and this one, I do believe that there's something to it. Many people say that it works, and the explanation is straightforward:
Whenever the body is forced to take in more air than it needs, we’ll exhale too much carbon dioxide, which will narrow the blood vessels and decrease circulation, especially in the brain. With just a few minutes, or even seconds, of overbreathing, brain blood flow can decrease by 40 percent, an incredible amount...Disturbances in these areas can elicit powerful hallucinations, which include out-of-body experiences and waking dreams. If we keep breathing a little faster and deeper, more blood will drain from the brain, and the visual and auditory hallucinations will become more profound.
...Consciously sustaining these stress signals long enough may trick the more primitive limbic system into thinking the body is dying. This could explain why so many people experience sensations of death and rebirth during Holotropic Breathwork.
Noses are sexy
I more or less knew what to expect when I started this book. Nose breathing, Wim Hof, jawbones—all stuff I'd come across online that eventually led me to this book. The biggest unexpected surprise was how interesting the nose's anatomy is:
...scientists have known for more than a century that the nostrils do pulse to their own beat, that they do open and close like flowers throughout the day and night.
The phenomenon, called nasal cycles, was first described in 1895 by a German physician named Richard Kayser. He noticed that the tissue lining one nostril of his patients seemed to quickly congest and close while the other would mysteriously open. Then, after about 30 minutes to 4 hours, the nostrils switched, or “cycled.” The shifting appeared to be influenced less by the moon’s mysterious pull and more by sexual urges.
I had noticed moments in the past where one nostril felt more stuffed up than the other, but had never thought about it too much. It turns out that's really a thing. And that last comment about "sexual urges" leads into this:
The interior of the nose, it turned out, is blanketed with erectile tissue, the same flesh that covers the penis, clitoris, and nipples. Noses get erections. Within seconds, they too can engorge with blood and become large and stiff. This happens because the nose is more intimately connected to the genitals than any other organ; when one gets aroused, the other responds. The mere thought of sex for some people causes such severe bouts of nasal erections that they’ll have trouble breathing and will start to sneeze uncontrollably, an inconvenient condition called “honeymoon rhinitis.”
In the section above where I shared how nasal breathing increases the body's nitric oxide, I left out this parenthetical remark:
(The popular erectile dysfunction drug sildenafil, known by the commercial name Viagra, works by releasing nitric oxide into the bloodstream, which opens the capillaries in the genitals and elsewhere.)
Who knew?
Conclusion
Nestor is a little too ready to take some of these ideas at face value. Hopefully the success of his book inspires scientists to study breath further so we can fully separate the fact and the fiction. But even if, like me, you're not buying some of it, there's still a core of interesting and valuable insights. I don't think I'm about to start following the Wim Hof method, but I'll definitely be doing more nasal breathing. In fact, my mouth is taped closed right now.