What Is Sleep Apnea?
A literal answer to the question “What is sleep apnea?” is that the term apnea comes from two Greek words meaning “no breath.” Apnea is literally a state of breathlessness, caused by the body itself rather than caused by external forces.
Sleep apnea, as you might suppose, is a state of breathlessness during sleep. It’s also possible, although quite rare, to experience apnea while awake. But because sleep apnea occurs while we are asleep, most people who have it are unaware of their condition. Obstructive sleep apnea occurs when air passages or blocked. Central sleep apnea occurs when the normal reflex reactions that power sleep become inefficient.
Breathing and sleeping are things most of take for granted. If we have a stuffy nose or a sore throat during the day, we take measures to make breathing easier. Any obstruction to breathing freely while we are awake is instantly removed.
Breathing problems during sleep, however, aren’t instantly addressed. It literally takes the imminent threat of suffocation to wake some of us from sleep, and then just for a second or two, in some cases, dozens or hundreds of times every night. While these repeated interruptions of sleep make deep sleep impossible, the idea that poor sleep is caused by poor breathing simply never occurs to most people who have sleep apnea and related problems.
What Goes Wrong During Sleep Apnea?
Most mammals sleep, but only humans have sleep apnea. Only humans can choke and die. Three unique features of human anatomy that make it possible for us to speak also leave us vulnerable to attacks of breathlessness while sleeping and vulnerable to choking.
1. Humans have necks.
Our facial bones narrow dramatically at the jaw and neck so we can move our faces from side to side without moving our shoulders. This also enables us to make a greater variety of sounds with our mouths and lips. The downside of this anatomical arrangement, which scientists call klinorynchy, is that our breathing passages narrow as they connect to the throat.
2. Humans have soft palates.
Humans have a voice box in their throats. Most animals (and human babies) have a voice box just behind the palate at the roof of the mouth. In animals, the palate is hard. In humans, the palate is soft and floppy. A soft palate enables humans to make a much wider range of pitches, but it can also drop down and interfere with the passage of air from the nose. In babies, the upper fold of the voice box, the epiglottis, extends up into the throat and protects against choking on milk. By the time the voice box begins to descend into the throat, at the age of nine or ten months, babies have learned how to swallow.
3. Humans have relatively long throats.
Humans have relatively long throats, capable of making low-frequency sounds. A longer throat is more susceptible to closure, especially from the weight of the chin.
What all this means is that the way we turn our faces has a lot to do with how well we breathe. Many people who have sleep apnea can breathe well when they sleep on their stomachs or their sides but they can’t breathe when they sleep on their backs.
It also means that anything that makes the palate looser interferes with breathing. The roof of the mouth can literally sag down and cut off the passage of air. Sinusitis and tonsillitis make the problem worse.And it means that weight on the throat, such as the weight of body fat, can interfere with breathing. The longer the neck, the greater the problem from excessive weight.
While we are awake, we can compensate for all of these problems, especially when we are standing up or sitting up. When we are asleep, however, we don’t shift positions to keep air flowing. And all of these problems can be made worse by the teeth and the tongue.
Your Teeth, Your Tongue, and Sleep Apnea
In the 1920’s and 1930’s, a famous dentist named Weston Price examined teeth of people in over 60 countries. He found that people who ate diets low in sugar, not surprisingly, tended to have great teeth. People who didn’t have cavities and gum disease also had bridges that stayed wide, while people who had dental problems tended to have mouths that narrowed with age. The wider the mouth, the less pressure on the palate, and the easier it is to breathe through the nose.
A wider mouth also provides more air pressure to keep the tongue in place. When the mouth is narrowed, and the throat is narrowed, the air passing down from the nose moves faster. Faster air is lighter air. Lighter air results in lower airway pressure that sets up a partial vacuum that in turn pulls the tongue into the throat.
When people are standing up, sitting up, or lying on their sides or stomachs, the force of gravity keeps the tongue from falling backward into the throat no matter how fast air flows through the throat. When someone who has narrowing of the mouth and throat lies down, however, one of two things can happen.
1. Your tongue falls back partially blocking your throat. This causes your palate to collapse and flutter, making snoring sounds.
2. Your tongue falls back to completely block your throat. Your brain senses that your tongue is about to obstruct your throat and you are about to suffocate and wakes you back into light sleep for 1 to 3 seconds so you can move your tongue. Or your brain senses that suffocation is imminent and you wake up completely, gasping for breath.
Both phenomena can repeat themselves hundreds of times per night. And other health conditions can make apnea a lot worse. If you have an allergy, or a cold, sinusitis, tonsillitis, or stuffy nose, there will be at least slight inflammation in your airways, making them narrower. This creates suction that makes weak tissues in the palate and throat even more vulnerable to collapse.
The suction also tugs at the esophagus. The sphincter that holds acid and bile in the stomach opens and allows small amounts of irritating digestive juices into the throat. This creates even more inflammation, which makes the airways even narrower, which creates more suction, which pulls even more acid out of the stomach. The narrower the airway, the harder it is for it to expel the mucus that accumulates during infection, and more infection is trapped in the sinuses, reinfecting the throat every time the nasal passages begin to improve. Let untreated, sleep apnea becomes a self-perpetuating process. And in about 2% of women and about 4% of men, this process happens so often that they could be diagnosed with sleep apnea.
The Medical Definition of Sleep Apnea
Breathing that stops completely is called apnea. Breathing that is significantly diminished for 10 seconds or more is called hypopnea. When either apnea or hypopnea occurs 15 or more times per hour in an adult, a diagnosis of obstructive sleep apnea may be made under the criteria used by insurance companies. Sleep apnea in children requires just one incident per hour.
The problem with any cutoff point is that some people who have “obvious” sleep apnea won’t be diagnosed as having sleep apnea. An adult who has 14 episodes of halted breathing per hour lasting 9 seconds each will get a label of “idiopathic (the doctor’s term for “we don’t know why”) sleep disturbance. But before people are diagnosed with sleep apnea, they are usually diagnosed with depression, diabetes, obesity, high blood pressure, or chronic fatigue syndrome. And people who have “idiopathic sleep disturbances” also tend to develop gastroesophageal reflux disease, congestive heart failure, low blood pressure, vertigo, temperomandibular joint syndrome (TMJ), irritable bowel syndrome, migraine headaches, cluster headaches, fibromyalgia, hypothyroidism, obsessive-compulsive disorder, excessive daytime sleepiness, sleep-onset insomnia, and strange ache and pain symptoms than other people—but they won’t usually get treatment for sleep apnea.
Apnea expert Dr. Steven Park estimates that 9% of women and 24% of men suffer 5 or more sleep apnea episodes per hour. That means 7% of women and 20% have problems with apnea but won’t get the official diagnosis that qualifies them for insurance coverage. They instead get diagnoses of depression, diabetes, obesity, high blood pressure, or chronic fatigue syndrome.
Or a truck driver gets a career-ending ticket for a silly traffic mistake. Or a tired young mother crashed into a tree while driving her kids to school. Or an executive at the top of her career makes an error in judgment that forces early retirement.
The overwhelming majority of people who suffer sleep apnea don’t know about apnea symptoms so don’t find out they have sleep apnea until it makes permanent changes in their lives. There are tell-tale symptoms of sleep apnea, however, that mean you should try at-home apnea testing or schedule an appointment with your doctor.
