Understanding Sleep Apnea: A General Overview

Sleep apnea is a severe sleep disorder that, if left untreated, can lead to severe health problems. The word apnea means a cessation of breathing, so sleep apnea means that one stops breathing during sleep. Although your body will force a deep breath eventually, people with sleep apnea can go 10 seconds or more without breathing per episode, and these episodes can happen up to 100 times an hour.

In this article, we will discuss an overview of sleep apnea including symptoms, complications, and treatment strategies. However, consider these stats regarding sleep apnea:

  • 18 million American adults have sleep apnea[1]
  • Many experts believe sleep apnea is underdiagnosed in up to 80% of patients with moderate to severe sleep apnea
  • 1 in 5 adults has mild obstructive sleep apnea[2]
  • Sleeping partners of people with sleep apnea can lose up to one hour of sleep per night

According to these sources, a significant number of people do not know they have sleep apnea. Also, many will not find out for a long time unless either a family member or friend points it out or they develop a serious health complication from it.

Before we get into the 2 main types of sleep apnea, let us start by briefly discussing what regular sleep looks like.

What Is Regular Sleep?

While experts are still not entirely sure why we need sleep, one thing is for sure: many creatures from jellyfish to humans drift at regular intervals into soundless slumber. We know more about "how" we sleep than "why" we sleep. During regular sleep, your body goes through 4 cycles: 2 cycles of light sleep and 2 cycles of deep sleep. There are also longs periods of rapid eye movement (REM) sleep that happen when sleep is uninterrupted. Throughout these various cycles, the brain waves change and signify dream states or periods of deep sleep.

Some people describe high-quality sleep as having spent at least 85% of your time in bed asleep[3] and waking up no more than once per night. By this definition, getting great sleep means we stay asleep longer and have almost no interruptions.

However, sleep apnea disrupts regular sleep. When you have long periods of apnea at night, your brain must jolt your body out of sleep to take a deep breath. You may not remember these "jolting" episodes, but they are strong enough to kick you out of deep sleep and displace you into a light sleep.

According to the American Sleep Association[4], the consequences of interrupted sleep can lead to problems with:

  • The cardiovascular system
  • The immune system
  • Memory consolidation
  • Response time
  • Attention
  • Hunger
  • Mood

Without regular sleep, general health slowly declines until the symptoms become too great to ignore.

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Types of Sleep Apnea

What does sleep apnea look like? There are 2 main types of sleep apnea: central and obstructive.

Central Sleep Apnea
In central sleep apnea, the brain doesn’t send the right signal to breathe during the night. This misfire can happen for many reasons such as a stroke, narcotic use, or a heart disorder. The risk of having central sleep apnea is much lower, but it is generally considered a severe acute problem because it can lead to complete respiratory failure.

Obstructive Sleep Apnea
Obstructive sleep apnea occurs when a person’s tongue and throat muscles relax too much during the night and periodically close off the airway, thus ceasing all airflow through the lungs. Of the 2 types, obstructive sleep apnea is the most common and can be caused by:

  • A narrowed airway
  • Sedation
  • Alcohol
  • Neck circumference
  • Obesity

Obstructive Sleep Apnea Breathing

While central sleep apnea may signify severe changes in the brain and central nervous system, obstructive sleep apnea usually points to lifestyle and positional issues that can cause the airway to close off during sleep.

Signs and Symptoms

One of the most challenging aspects of diagnosing sleep apnea is that it occurs when a person is asleep, and this makes it challenging to connect daytime symptoms with nightly sleep apnea. If you suspect that you have sleep apnea, there are several signs to look out for:

  • Daytime sleepiness
  • Mood disturbances
  • Morning headaches
  • Trouble staying asleep
  • Dry throat in the morning

There are also two signs that you will have to ask a family member or friend to look out for a while you are asleep:

  • Cessation of breathing at regular intervals
  • Snoring

Although snoring may seem harmless or even humorous, it is a sign that the throat is closing off the airway. The only way to generate the sound of snoring is to pull the tongue back against the throat so it can vibrate on inhalation.

Any of these above symptoms can suggest sleep apnea. If present, bring them up with your doctor and request to have a proper sleep study for confirmation.


The most severe complications of sleep apnea include stroke and cardiovascular disease. There is a significant lack of oxygen throughout the night caused by sleep apnea, and low oxygen levels force the heart muscle to work harder. The American Heart Association has reported that sleep apnea is associated with high blood pressure, stroke, arrhythmia, and heart failure[5].

Some other serious complications can occur including:

  • Metabolic syndrome
  • Liver failure
  • Memory problems
  • Type 2 diabetes

Complications like these are serious and can progress into chronic illnesses. Once you have a diagnosis, you should explore your treatment options.

Treatment: Lifestyle and Physician-Prescribed

Treatment options for sleep apnea range from lifestyle changes to physician-prescribed medical devices.

Lifestyle Changes

Obstructive sleep apnea is associated with obesity, and this correlation is most likely present because excess adipose tissue around the neck causes the upper airway to collapse when combined with normal breathing. Losing weight can help keep excess adipose tissue off the neck and prevent airway collapse.

Using less alcohol can also help relieve obstructive sleep apnea. Alcohol relaxes the throat muscles and can cause the tongue to fall back more easily. This combination leads to airway collapse. Excessive alcohol use can also sedate your ability to breathe deeply during sleep and lead to even more dangerous risks such as respiratory depression and aspiration of stomach contents.

One simple way to instantly relieve snoring in many cases is to sleep on your side or stomach instead of sleeping on your back. Sleeping on your back will lead to obstruction if the conditions are right because gravity is pulling the tongue back where it can block the upper airway. However, when you are on your side or stomach, gravity works in your favor and pulls the tongue away from the back of the throat, which may prevent snoring.

Physician-Prescribed Medical Devices

One of the most common devices used to treat obstructive sleep apnea is called a continuous positive airway pressure (CPAP) mask. A CPAP mask is placed over your nose and creates back pressure that you must exhale against during sleep. The back pressure stents open your throat muscles so normal airflow can continue uninterrupted.

CPAP devices come in many different configurations including under the nose prongs, a nasal mask, or even a total face mask. The goal for CPAP use is to make sure you are comfortable with the machine so you can easily fall asleep with it.

CPAP Machine for Sleep Apnea

Some cases of obstructive sleep apnea can be treated with an oral appliance that works by adjusting the jaw position to prevent the tongue from falling back against the throat. However, there are also more severe cases of obstructive sleep apnea that may require surgery to correct.


Sleep apnea is a severe and chronic medical condition that can lead to heart disease and stroke if left untreated. Moreover, since many people that have sleep apnea are undiagnosed, it is essential to be aware of the symptoms if you suspect that you or a loved one might have it. The good news is that there are a lot of treatment options available to alleviate sleep apnea and restore your quality of life.

Information on this page is for reference and educational purposes only. For more information about sleep apnea, talk to your doctor or primary care provider.

Page last updated: October 3, 2018

[1] National Sleep Foundation. Sleep Apnea. https://sleepfoundation.org/sleep-disorders-problems/sleep-apnea
[2] Berger Henry ENT. Sleep Apnea Statistics and Facts. Last updated: June 21, 2016. https://www.bergerhenryent.com/sleep-apnea-statistics-2016/
[3] The Cut. What It Actually Means to Get a Good Night's Sleep. Published: January 26, 2017. https://www.thecut.com/2017/01/what-a-good-nights-sleep-looks-like-by-the-numbers.html
[4] American Sleep Association. Why is Sleep Important? https://www.sleepassociation.org/sleep-news/why-is-sleep-important/
[5] American Heart Association. Sleep Apnea and Heart Disease. Last reviewed: July 31, 2015. https://www.heart.org/HEARTORG/Conditions/More/MyHeartandStrokeNews/Sleep-Apnea-and-Heart-Disease-Stroke_UCM_441857_Article.jsp#.WySTnFMvwck/

About Scott Ridl: Scott joined American Medical Sales and Rentals in 2008 as a Web Manager and Content Writer. He is a writer and designer. He is extensively trained on oxygen therapy products from leading manufacturers such as Inogen, Respironics, Chart, Invacare, ResMed and more. Scott works closely with respiratory therapists and oxygen specialists to educate the community about oxygen therapy products, COPD, asthma and lung diseases. He writes weekly columns and is passionate about educating the community on oxygen therapy and respiratory issues.

3 thoughts on “Understanding Sleep Apnea: A General Overview”

  • D Lilli Barnett
    D Lilli Barnett July 13, 2018 at 6:00 am

    Great informative and very clear article on sleep Apnea thank you!

  • Michael Brennick, PhD
    Michael Brennick, PhD July 13, 2018 at 8:17 am

    Dear Scott Ridl,
    My father uses supplemental O2 for asbestosis related lung disease. Initially it was prescribed to alleviate nocturnal desaturations and morning headache. Now, he uses around 2.5 to 3 l/min all day and all night. I noticed that he does not snore much while asleep. Perhaps the slight Nasal flow and related (supplemental O2) pressure helps? I do know that in general O2 is NOT advised for sleep apnea because oxygen tends to depress the muscle activity of the Genioglossus and other upper airway dilator muscles.

    However, in the case where O2 is required to alleviate nocturnal desaturation the effect may be more helpful than anyone has noticed or reported on? I would suspect that there may be NO controlled clinical studies testing the possible improvement in sleep apnea (Obstructive sleep apnea or central origin sleep apnea or mixed OSA and central apnea) using O2 supplementation with diagnosed desaturating patients (with COPD or Asbestosis lung disease) like my father. It might be worthwhile to search on this specific group of patients to see what improvement if any is realized with O2 supplementation?

    I am affiliated with University level research in sleep apnea at Johns Hopkins Medical school as a senior research assistant so I will ask of my supervising professors if the specific research question above has been examined in any clinical trials.
    Respectfully yours,
    Michael Brennick. PhD

  • Joseph Matthews
    Joseph Matthews July 13, 2018 at 1:30 pm

    Combination therapy may be successful when CPAP is poorly tolerated. For example, supplemental oxygen along with an oral device for mandibular advancement may be more comfortable than CPAP masks and equally effective.


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