Egil P. Harvold’s hideous experiments in the 1970s and 80s would not go over well with PETA or with anyone who has ever really cared for animals. Working from a lab in San Francisco, he gathered a troop of rhesus monkeys and stuffed silicone deep into the nasal cavities of half of them, leaving the other half as they were. The obstructed animals couldn’t remove the plugs, and they couldn’t breathe at all through their noses. They were forced to adapt to constant mouthbreathing.
Over the next six months, Harvold measured the animals’ dental arches, the angles of their chins, the length of their faces, and more. The plugged-up monkeys developed the same downward growth pattern, the same narrowing of the dental arch, crooked teeth, and gaping mouth. Harvold repeated these experiments, keeping animals obstructed for two years. They fared even worse. Along the way, he took a lot of pictures.
The photographs are heart-wrenching, not only for the sake of the poor monkeys, but because they also offer such a clear reflection of what happens to our own species: after just a few months, faces grew long, slack-jawed, and glazed over.
Mouthbreathing, it turns out, changes the physical body and transforms airways, all for the worse. Inhaling air through the mouth decreases pressure, which causes the soft tissues in the back of the mouth to become loose and flex inward, creating less overall space and making breathing more difficult. Mouthbreathing begets more mouthbreathing.
Inhaling from the nose has the opposite effect. It forces air against all those flabby tissues at the back of the throat, making the airways wider and breathing easier. After a while, these tissues and muscles get “toned” to stay in this opened and wide position. Nasal breathing begets more nasal breathing.
“Whatever happens to the nose affects what’s happening in the mouth, the airways, the lungs,” said Patrick McKeown during a phone interview. He’s a bestselling Irish author and one of the world’s leading experts on nasal breathing. “These aren’t separate things that operate autonomously—it’s one united airway,” he told me.
None of this should come as a surprise. When seasonal allergies hit, incidences of sleep apnea and breathing difficulties shoot up. The nose gets stuffed, we start mouthbreathing, and the airways collapse. “It’s simple physics,” McKeown told me.
Sleeping with an open mouth exacerbates these problems. Whenever we put our heads on a pillow, gravity pulls the soft tissues in the throat and tongue down, closing off the airway even more. After a while, our airways get conditioned to this position; snoring and sleep apnea become the new normal.
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It’s the last night of the nasal obstruction phase of the experiment, and I am, again, sitting up in bed and staring out the window.
When a Pacific breeze blows in, which it does most nights, the shadows of the trees and plants on the backyard wall across from my bedroom start to move and groove in a chromatic kaleidoscope. One moment they reorganize into a cadre of Edward Gorey gentlemen in waistcoats, the next into crooked Escher staircases. Another gust of wind, and these scenes disintegrate and reform into recognizable stuff: ferns, bamboo leaves, bougainvillea.
This is a long way of saying: I can’t sleep. My head’s been propped up on pillows and I’ve been taking notes on this creepy tableau for 15, 20, maybe 40 minutes. I unconsciously try to sniff and clear my nose, but instead get a jolt of pain in my head. It’s a sinus headache, and in my case, self-inflicted.
Each night for the past week and a half, I’ve felt as if I was getting softly choked to death in my sleep and my throat was closing in on itself. Because it is, and because I am. Forced mouthbreathing was very likely changing the shape of my airways, just as it did with Harvold’s monkeys. The changes weren’t happening in a matter of months, either, but days. It was getting worse with every breath I took.
My snoring has increased 4,820 percent from ten days ago. For the first time that I’m aware of, I’m beginning to suffer from obstructive sleep apnea. At my worst, I’ve averaged 25 “apnea events,” meaning I was choking so severely that my oxygen levels dropped to below 85 percent.
Whenever oxygen falls below 90 percent, the blood can’t carry enough of it to support body tissues. If this goes on too long, it can lead to heart failure, depression, memory problems, and early death. My snoring and sleep apnea are still far below that of any medically diagnosed condition, but these scores were getting worse the longer I stayed plugged up.
Every morning Olsson and I would listen to recordings of ourselves sleeping the night before. We laughed at first, then we got a bit frightened: what we heard weren’t the sounds of happy Dickensian drunks, but of men being strangled to death by our own bodies.
“More wholesome to sleep . . . with the mouth shut,” wrote Levinus Lemnius, a Dutch physician from the 1500s who was credited as one of the first researchers to study snoring. Even back then, Levinus knew how injurious obstructive breathing during sleep could be. “For they that sleep with their Jaws extended, by reason of their breath, and the air tossed to and fro, have their tongues and palates dry, and desire to be moistened by drinking in the night.”
This was another thing that kept happening to me. Mouthbreathing causes the body to lose 40 percent more water. I felt this all night, every night, waking up constantly parched and dry. You’d think this moisture loss would decrease the need to urinate, but, oddly, the opposite was true.
During the deepest, most restful stages of sleep, the pituitary gland, a pea-size ball at the base of the brain, secretes hormones that control the release of adrenaline, endorphins, growth hormone, and other substances, including vasopressin, which communicates with cells to store more water. This is how animals can sleep through the night without feeling thirsty or needing to relieve themselves.
But if the body has inadequate time in deep sleep, as it does when it experiences chronic sleep apnea, vasopressin won’t be secreted normally. The kidneys will release water, which triggers the need to urinate and signals to our brains that we should consume more liquid. We get thirsty, and we need to pee more. A lack of vasopressin explains not only my own irritable bladder but the constant, seemingly unquenchable thirst I have every night.
There are several books that describe the horrendous health effects of snoring and sleep apnea. They explain how these afflictions lead to bed-wetting, attention deficit hyperactivity disorder (ADHD), diabetes, high blood pressure, cancer, and so on. I’d read a report from the Mayo Clinic which found that chronic insomnia, long assumed to be a psychological problem, is often a breathing problem. The millions of Americans who have a chronic insomnia disorder and who are, right now, like me, staring out bedroom windows, or at TVs, phones, or ceilings, can’t sleep because they can’t breathe.
And contrary to what most of us might think, no amount of snoring is normal, and no amount of sleep apnea comes without risks of serious health effects. Dr. Christian Guilleminault, a sleep researcher at Stanford, found that children who experienced no apnea events at all—only heavy breathing and light snoring, or “increased respiratory effort”—could suffer from mood disorders, blood pressure derangements, learning disabilities, and more.