Living With OSA

Differences Between the 3 Types of Sleep Apnea Explained

There are three types of Sleep Apnea: Obstructive, Central, and Complex Sleep Apnea. Understanding the differences between each type is key to promoting healthy sleep. Let’s look at what makes each type unique! We’ll explore symptoms, causes, and treatments.

three type of sleep apnea diagram

Obstructive Sleep Apnea (OSA)

Obstructive Sleep Apnea is the most common form of Sleep Apnea and is a sleep disorder in which the soft tissues of the mouth and throat expand and relax during sleep. The relaxed muscles can block the airway, preventing air from reaching the lungs. This, in turn, lowers the blood oxygen content and can cause the user to wake up gasping or choking for breath.

Over the course of the night, the process repeats itself, and as a result, the person doesn’t get very good sleep.1

Symptoms of Obstructive Sleep Apnea

Symptoms of OSA can include the following:

  • Daytime Fatigue1
  • Falling Asleep While Tired or Bored1
  • Loud Snoring that Can Be Heard in Another Room1
  • Frequently Waking Up to Urinate1

Sleeping partners may notice that someone with OSA may stop breathing for five seconds or longer during the night.

Causes of OSA

OSA has many causes including:

  • Obesity1
  • Having a Narrow Throat1
  • Enlarged Tonsils or Adenoids1

Having one of these risk factors doesn’t necessarily mean that you’ll have or develop a sleep disorder. But if over time you notice your snoring get worse or your breathing stops repeatedly overnight, you may want to get it checked out.

Types of Obstructive Sleep Apnea

OSA is classified into three groups: mild, moderate and severe. Each group refers to the average number of times per hour the sleeping individual suffers an interruption in breathing. Severe OSA patients may see 30 or more interruptions in a single hour. There are 3 different types of Obstructive Sleep Apnea: mild, moderate, and severe.

A. Mild: Mild OSA is a condition in which 5 to 15 sleep interruptions occur each hour, resulting in an AHI score of 5 to 15. AHI stands for “Apnea Hypopnea Index” and is used to calculate the severity of Sleep Apnea.

B. Moderate: Moderate OSA is a condition in which 15 to 30 sleep interruptions happen each hour, creating an AHI of 15 to 30.

C. Severe: Severe OSA is a condition in which 30 or more sleep interruptions happen each hour, creating an AHI of over 30.

Tracking your AHI can be a measure of how your Sleep Apnea treatment is going. The lower your AHI, the better, more restful sleep you’re getting each night. If your Sleep Apnea treatment is working, you should see your AHI readings below 5, and it may be as low as 1. Your results will vary, but keeping an eye on your AHI is a good way to see how your treatment is going.

How to Treat Obstructive Sleep Apnea

CPAP therapy is the most common treatment for OSA. It works by introducing a constant flow of air from a CPAP machine into your mask. The continuous pressure helps keep the airways open and respiratory function at normal levels, which allows for easier breathing during sleep.

When used regularly, CPAP therapy can significantly reduce breathing complications, provide a better night’s sleep, and improve your overall health.

This is the most common out of the three types of Sleep Apnea. It is caused by the total or partial blockage of the airways during periods of rest or sleep. OSA doesn’t just happen while you’re sleeping; it can occur anytime an individual lies down. As long as the conditions are right for the airway to relax and the muscles of the throat to rest in the airway, OSA can occur.

three types of sleep apnea

Surgery may also be an option for severe cases and when other treatments have failed. There are different types of surgery for Sleep Apnea, including uvulopalatopharyngoplasty (UPPP), tonsillectomy, maxillomandibular advancement (MMA), and radiofrequency ablation (RFA). Your doctor will likely not recommend this option unless absolutely necessary.

Central Sleep Apnea (CSA)

CSA is a less common form of the condition compared to OSA. It is generally caused by medical concerns that affect the brain. CSA is a condition in which the signals to breathe are not sent by the brain, and as a result, the person does not draw a breath.

This is different from OSA in that there doesn’t have to be a blocked airway that prevents a person from breathing. Here’s a helpful article that explains the differences between Obstructive Sleep Apnea and Central Sleep Apnea.

Essentially, CSA patients experience respiratory distress as the brain fails to properly signal the muscles that control breathing function.

Parkinson’s patients, those who frequently take narcotics, or anyone who has experienced an infection that has affected the brain can suffer from CSA.

Symptoms of CSA

Symptoms3 of CSA include:

  • Stoppage of Breathing During the Night3
  • Shortness of Breath That Goes Away When Sitting Up3
  • Chest Pain at Night3
  • Difficulties Concentrating3
  • Mood Changes3

You’ll notice that many of these symptoms differ from OSA’s symptoms, such as loud snoring that can be heard in another room. It’s important to pay close attention to your symptoms, but know that a sleep study will be needed to confirm a diagnosis.

Causes of Central Sleep Apnea

There are several possible causes of CSA:

  • Cheyne-Stokes Syndrome3
  • Opioid-Induced Apnea3
  • Complex Sleep Apnea3
  • High-Altitudes3

We’ll go over these causes one at a time, as some of these may be unfamiliar to you.

  • Cheyne-Stokes Breathing: Commonly associated with congestive heart failure or stroke, Cheyne-Stokes is a condition in which there are periods of extremely shallow breaths resulting from a gradual decrease in the intensity and effort of breathing. Breathing decreases, and eventually, stops.
  • Opioid-Induced Apneas: Opioids can make your system extremely slow, as every part of your body reacts to the powerful sedatives. Breathing is no exception. During sleep, opioids can make breathing increasingly weaker, and eventually, this can lead to a cessation of breathing resulting in CSA.
  • Complex Apnea: Complex Sleep Apnea is a condition in which someone experiences both CSA and OSA at the same time. We’ll go over this in greater detail in the section below.
  • High Altitudes: Sometimes a higher altitude results in shallow breathing. The air is thinner and there’s less oxygen so it can be harder to breathe– creating perfect conditions for CSA.

how to treat the 3 types of sleep apnea

Treating Central Sleep Apnea

Although treatment options are a little different than with OSA, CPAP therapy is still the leading choice for most CSA cases. It works the same way by delivering a continuous flow of air from the CPAP machine to your mask.

The pressurized air keeps your upper airway open, which reduces symptoms of CSA3.

BiPAP, or bi-level positive airway pressure, is another treatment option for CSA. While similar to CPAP machines, a BiPAP machine modifies the level of air delivered to the patient based on whether they are breathing in or out. This helps those with respiratory issues as it demands less effort during exhalation3.

If CPAP or BiPAP therapy isn’t working, CSA patients are sometimes prescribed medication to stimulate breathing. Examples of these medications include Diamox, Theo-24, or Theochron.

Complex (Mixed) Sleep Apnea

Complex Sleep Apnea is a newcomer to the field of sleep medicine, having just been discovered in 2006. Researchers found that certain patients with apparent severe OSA were not completely helped by CPAP therapy. Through their research, they discovered that the real culprit was OSA mixed with CSA.

They realized that what they found was neither CSA nor OSA. It was actually a third type: Complex Sleep Apnea4.

Also called Mixed Sleep Apnea, this condition is a particularly dangerous combination of the other two types of sleep apnea: OSA and CSA. Some patients start off with OSA and then gradually shift to CSA – even after CPAP therapy. This isn’t very common, but it occurs enough that it is becoming a concern among medical sleep specialists5.

Treating Mixed Sleep Apnea

Treatment options are surprisingly still in development, but most doctors today will suggest the patient use a CPAP machine at a low-pressure setting. This helps ensure the individual doesn’t cause too much stress on their system and trigger an onset of CSA. CPAP and BiPAP machines are often suggested, with the sleep clinic determining which machine is providing the greatest benefit to the patient5.

For more information on Sleep Apnea check out our article “Everything You Need to Know About Sleep Apnea and How to Treat It” a comprehensive resource, and will help you better understand the condition and find out more information.

If you believe you have the symptoms of Sleep Apnea, make sure to contact your physician for a diagnosis and medical recommendations. You should also sign up for our newsletter! Our newsletter keeps you informed about the latest developments in Sleep Apnea, and also notifies you of the latest deals and money-saving coupons.

cpap bipap and apap therapy


1. American Lung Association. Obstructive Sleep Apnea (OSA) Symptoms, Causes & Risk Factors. Published on the American Lung Association’s official website. Accessed on September 27, 2018.

2. American Association of Sleep Technicians. Obstructive vs. Central Sleep Apnea: Key Differences and Treatment Options Published on the American Association of Sleep Technicians official website. Accessed on September 27, 2018.

3. Eckert, Danny J. et al. Central Sleep Apnea: Pathophysiology and Treatment. Published in the medical journal Chest in 2007. Accessed on September 27, 2018.

4. Mayo Clinic. Mayo Clinic Discovers New Type Of Sleep Apnea Published in the health news magazine Science Daily on September 4, 2006. Accessed on September 27, 2018.

5. Wang, Juan et al. Complex Sleep Apnea Syndrome Published in the medical journal “Patient Preference and Adherence” in 2013. Accessed September 27, 2018.


    • Hey Jane, studies have not been proven that there is a direct correlation between Sleep Apnea and weight. However, if you are overweight, you are at a higher risk of being diagnosed with Sleep Apnea. I would encourage you to speak with your doctor if you have concerns regarding your weight and Sleep Apnea.

      Please let us know if we can be of further assistance.

      Have a great day!

  1. Tiffany Sanner-Farrington Reply

    How can I tell which is the best mask for me if my REI is 87.4? I did the sleep test but can not afford another appointment with the Sleep Specialist. I have access to a Phillips Respironics Dream Machine and I am also trying to find out what my settings should be. I see my regular doctor tomorrow. Just looking for 2nd option. Thank you

    • Hi Tiffany, that’s a great question! Unfortunately, there isn’t any way to know which mask will best fit you. The only real way to know if a mask will work for you is to try the mask and this may require you to try several different masks before you find the one you’re most comfortable with.

      We sell all of our complete masks with free 30 day returns. If you purchase a mask, try it and find it uncomfortable, or just don’t like it, simply return the mask to us for a different mask, store credit, or refund. We even cover the return shipping cost by emailing you a return label!

      Regarding your machine settings, that is something to be determined by your doctor. If you happen to have the DreamStation Auto, settings aren’t required and the machine can be set so that you’ll receive the pressure you need on a breath by breath basis.

      For further questions, or concerns, please reach us at: 1-800-356-5221, or you may email us at:

      Best Wishes!

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