Sleep Apnea Explained – The Science Behind Sleep Apnea

In Sleep Disorders by JGrahamLeave a Comment

Sleep Apnea Explained

Now, let’s not get all freaked out here, you should know sleep apnea is a very common as well as very treatable condition.  I’m assuming you’ve made it here because you have been diagnosed with or think you may have sleep apnea.  Just know, you are not alone.  It’s estimated that over 80 million Americans have sleep apnea and don’t even know it.

With that said, although common, it’s also common for people to be a stubborn pain in the arse and neglect it, myself included. I have to sleep with a CPAP machine nightly and am not particularly crazy about it.

But, I have to wear it. Sleep apnea is not a disorder that should be looked at as a non-issue  The long terms effects can take it’s toll on the body and in some cases even be fatal.  So with that in the back of my mind, I think I can deal with the inconvenience of my mask and all involved with it.


In order to give you a better understanding of this condition, I’m going to break down what is going on behind the scenes to try and explain the science behind sleep apnea. Please note, This is not exactly going to be the most medically professional article you will ever read, but it’s the only way I know how to explain this condition in a way that is easily digestible, so bear with me.


Ok, kids lets start our lesson with vocabulary definitions.

Apnea or apnoea

1.a temporary suspension of breathing, occurring in some newborns (infant apnea) and in some adults during sleep (sleep apnea)

During apnea, there is no movement of the muscles of inhalation, and the volume of the lungs initially remains unchanged.




This is the most common type of the disorder and is typically caused by an abnormal relaxation of the throat muscles. This is the one associated with the loud, dump truck making sweet love to a bear under a jet engine kind of snoring your partner has grown to know and love.

Under normal circumstances, body-regulated airflow takes place during the night and the throat muscles tense and relaxes parts of your esophagus and soft palate to support breathing.

In the case of obstructive sleep apnea, your tongue, soft palate are conspiring to kill you.  Not really, but in short, your muscles relax as you descend into REM sleep; and in some cases this relaxation kinda causes the muscles to flop over your airway, restricting the flow of oxygen to the lungs.


  • Snoring
  • Waking up suddenly and feeling like you’re gasping or choking
  • Daytime sleepiness or fatigue.
  • Dry mouth or a sore throat when you wake up
  • Headaches in the morning
  • Sexual Dysfunction
  • Trouble concentrating, forgetfulness, depression, or irritability
  • Night Sweats
  • Restlessness during sleep
  • Trouble getting up in the mornings more information read here


Central sleep apnea takes place when your brain decides to go hipster and proclaim that sending signals to the parts of your body that control breathing is not cool anymore.

It’s not that something is restricting your breathing, it’s that your brain just doesn’t tell the body anything.   This variant is usually associated with serious illness, especially an illness in which the lower brain stem.

Conditions that may be associated with central sleep apnea include the following:

  • Congestive heart failure
  • Hypothyroid Disease
  • Kidney failure
  • Neurological diseases, such as Parkinson’s disease, Alzheimer’s disease, ALS or Lou Gehrig’s disease
  • Damage to the brain stem caused by encephalitis, stroke, injury, or other factors


Complex sleep apnea syndrome is a rare form of the disorder that is actually a combination of central sleep apnea and obstructive sleep apnea, which both occur simultaneously. The ultimate in body betrayal.


To better understand how sleep apnea can change your body’s normal operations. We need to understand how our body operates under normal circumstances.

Your body is made up of cells…lots of em. Combined, these cells form tissue. Those tissues go on to form organs, so on so forth.  These cells, tissue, and organs in your body require oxygen to thrive and function their best.

So let’s start with step one.  Take a deep breath.Image

You bring oxygen into your body by breathing, obviously, As you inhale, air moves down the trachea into the bronchi, After passing into the many bronchioles, it finally arrives into some of the millions of tiny sacs called alveoli.

Oxygen passes through the walls of each alveolus into the tiny capillaries that surround it. The oxygen enters the blood in the tiny capillaries, hitching a ride on red blood cells and traveling through layers of blood vessels to the heart.




The heart’s job is to then distribute blood and oxygen to all of your body. When your heart beats, oxygenated blood is then pumped to your cells to keep them alive and healthy.  Once your blood deposits its oxygen supply into your cells and organs, it travels back to the heart to dispose of the waste in the form of carbon dioxide on the exhale. Rinse, Lather, Repeat.



One of your brains many functions is to monitor the amount of oxygen in your blood. Kind of like an O2 sensor in a vehicle, it’s constantly monitoring the levels of carbon dioxide and oxygen in your bloodstream.

It regulates the amount of oxygen in your body by controlling the number of breaths you take in a minute, and how deeply you breathe in and out.

When the brain senses there’s too much oxygen in your blood, your brain tells the body to chill out by taking fewer breaths and regulating your heart rate.

For example, when you’re relaxed, just hanging around, playing Nintendo, your cells are operating at low capacity because your body is in a resting state.

Let’s say, after doing nothing but playing Nintendo and stuffing your face for the last month;  you realize you now look like Santa Clause and need to lose some weight.  Queue the exercise!  Time to go for a run.

During your run, the muscles in your body are called into action to support your activities.  In order to support your muscles at this heightened level, your cells and muscle tissue need more blood and oxygen to keep functioning.  At this point, the brain notices there is a significant chemical change and moves into action.

The brain now has to supply your body with the resources it needs, so it coordinates with the lungs and heart.   You can think of it as a chain of emails being firing off to start a project.

Your brain detects a need for more oxygen so it triggers the muscles in the diaphragm in order to breathe faster and deeper to get more oxygen into the lungs.

The brain then says I need to next day air this O2 via the bloodstream to the legs quickly. So, your heart beats harder and faster to distribute the increased amount of oxygenated blood to where it needs to go to support the muscles being exerted.


Getting to it, but I have one more thing to mention while it’s on my mind.

At night you go through different levels of sleep, you go from a light sleep to a deep level of sleep.  This deep level of sleep is called rapid eye movement or REM.

During REM sleep your body relaxes muscle tone, And when I say relaxes, basically,  I mean enters a state of paralysis. This state of sleeping allows our body to rejuvenate muscles, regulate hormones, fight diseases, and reduce inflammation in joints or repair injuries.  It’s basically our body’s version of a reboot.

You can get more information about the states of sleep here


When you start making your ways through the phases of sleep,  the muscles in your airway relax more and more to the point of blocking your airway.  When this blockage occurs you stop breathing, and this ladies and gentlemen is called an apnea.  A typical apnea can last anywhere between 5 up to 40 seconds. And these can happen multiple times throughout the night.

So, what happens when sleep apnea occurs?  Your brain switches into survival mode and all the fight or flight mechanisms kick in.The brain detects a lack of oxygen and signals your body to breathe faster and for your heart to pump harder,  just like in our running example.  But, in this scenario we have a small problem, your airway is blocked by some relaxed and flappy tissue. Because of this, oxygen now has no way to enter your lungs.

At this point, your brain is in the process of losing it’s s#%t and signals the heart to start pumping faster to make up for the lack of oxygen, as this happens your blood pressure starts to elevate.  It is then followed by a release of stress hormones like adrenaline and cortisol to wake you up. This adrenaline release shocks your system to wake you up just enough to regain muscle tone in your airways.  This regained muscle tone and a flood of adrenaline is what wakes you and causes the gasp for breath or a loud snore. Which in turn, allows you to breathe, and with breathing restored back to normal, your heart rate slows down, your blood pressure lowers, and the oxygen and hormone levels in your blood slowly start to regulate.


Sleep apnea usually starts off as a mild annoyance, but the longer it goes untreated, the more damage you are doing to your body.

Think about it, when your apnea is over, you fall back asleep, so your airway relaxes again, and as you would guess, the entire cycle of obstructed breathing repeats itself. This goes on all night, or at least until your partner elbows you for disturbing their sleep. In fact, this cycle can repeat itself as many as 100 times or more per night depending on the severity of your apnea.

This repetitive cycle all night, every night is taxing the hell out of your heart.  It’s having to work twice as hard when it should be resting and replenishing. With this happening all night long, you’re obviously not sleeping, at least, you are not getting the restorative REM sleep your body needs to function.  This is why most people that have sleep apnea are constantly tired. They never sleep. And on a side note,  this makes them just as dangerous as a drunk driver behind the wheel in the morning.

These increased levels of adrenaline, catecholamines, and cortisol, released due to the stress of the apnea leads to hyperglycemia or elevated blood sugar levels. Adrenaline alone can cause changes in your blood sugar, so if you’re a diabetic, your blood sugars can especially be hard to manage during the night.

The repeated lack of oxygen can also elevate your red blood cell count.  According to Sleep Review Magazine, elevated red blood cell count, or a high hematocrit is an indicator of a lack of oxygen in a person’s body. In response to these low oxygen rates, the body creates more blood cells to “carry more oxygen to account for the shortage.”

If left untreated you are looking at the possibility of the following conditions:

  • high blood pressure
  • congestive heart failure
  • heart attack
  • stroke
  • diabetes
  • obesity
  • buying the farm


Not necessarily by sleep apnea itself, but If there’s underlying heart condition, these multiple episodes of low blood oxygen (hypoxia or hypoxemia) can lead to sudden death from an irregular heartbeat.


Continuous positive airway pressure or CPAP the go-to method of treatment for sleep apnea. It’s effective,  but also customizable for each patient.

CPAP resolves sleep apnea  by introducing pressurized room air into your breathing airway at a sufficient pressure to keep your relaxed airway open during all levels of sleep


  •  Weight loss
    I can’t stress this one enough.  Any extra weight taken off of your body is a good thing.  But especially the excess weight around your neck.
  • Quit smoking
    Nicotine is highly addictive and destructive.  Usually, within the first hour of sleep, nicotine acts as a stimulant, reducing the number of apneas and hypopneas during sleep.  However, as nicotine withdrawal continues throughout the night, sleep apnea increases, possibly due to the “rebound effect” of nicotine withdrawal.  Smoking causes upper airway inflammation.  This inflammation causes the nose, uvula, and throat to swell, which reduces the space in the airway.
  • Avoid alcohol, sleeping pills, and sedatives
    These items are considered relaxants, and any more relaxation to the muscles in the neck can make the blockage to the airway worse.
  • Do not take caffeine and heavy meals within two hours of going to bed.
  • Regularize your period of sleep.

 Other methods of treating sleep apnea include:

  • Dental Appliances which reposition the lower jaw.  The results of these appliances can be very effective. It just depends on the source of obstruction.  I Highly recommend going this route before the cpap if this works for you.
  • Nasal expiratory positive airway pressure where a disposable valve covers the nostrils
  • Upper airway surgery to remove tissue in the airway.
  • Hypoglossal Nerve Stimulation where a stimulator is implanted in the patient’s chest with leads connected to the hypoglossal nerve that controls tongue movement as well as to a breathing sensor. The sensor monitors breathing patterns during sleep and stimulates the hypoglossal nerve to move the tongue to maintain an open airway.

You can review and purchase these mouthpieces and sleepaids here.


Well, Are you

  • Male
  • Obese (BMI >30)
  • Diagnosed with hypertension
  • Use alcohol or sedatives excessively
  • Have upper airway or facial abnormalities
  • Smoke
  • Have a family history of OSA
  • Have a large neck circumference (>17” men; >16” women)
  • Suffer from endocrine and metabolic disorder


Lose some weight!  Out of all the risk factors weight is the easiest ones to tackle when dealing with sleep apnea.  I know, that’s easier said than done, but you gotta do it.


As you can see your body is made up of many complex systems that work together to keep you healthy. Using your CPAP machine helps your body regain its normal balance and function and to be healthy.  Speaking from experience, It’s not the most comfortable thing in the world, but using your CPAP machine consistently is critical to your overall and long-term health.

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