Types of Sleep Apnea: Obstructive and Central Explained

Quick Takeaways:

• There are two main types of sleep apnea — obstructive and central — each with different causes and treatments.

• Obstructive sleep apnea (OSA) is the most common and happens when relaxed throat muscles block the airway during sleep.

• Central sleep apnea (CSA) occurs when the brain doesn’t send proper signals to control breathing.

• Understanding your specific type of sleep apnea can help you and your doctor choose the best treatment to improve your sleep and overall health.

 If you've been diagnosed with sleep apnea or you think you might have it, it can be helpful to understand the different types. Each type has its own causes, symptoms, and ways of being diagnosed. Understanding each type can give you a better idea of what treatment options might be available. Keep in mind that only a doctor can diagnose sleep apnea, and you'll want to work with your doctor to determine the best treatment plan for you.

What is sleep apnea?

Sleep apnea is a condition where breathing stops and restarts many times throughout the night. These interruptions can make it harder for your body to get enough oxygen. It can cause symptoms such as:¹

• Excessive daytime sleepiness

• Morning headaches

• Feeling irritable or moody

• Difficulty concentrating, struggling to feel present during the day

• Snoring or gasping for air while you sleep

There are two main types of sleep apnea:

• Obstructive sleep apnea (OSA)

• Central sleep apnea (CSA)

Because sleep apnea interrupts your sleep, you might feel tired or groggy during the day — despite getting more than seven hours of sleep. This can affect your focus, energy levels, and quality of life. Over time, untreated, sleep apnea can also increase your risk of developing other health issues, such as high blood pressure, heart disease, Type 2 diabetes and eye problems.² It can also increase the likelihood of workplace errors or traffic accidents.³

How common is obstructive sleep apnea (OSA)? 

Obstructive sleep apnea (OSA) affects nearly 1 billion people around the world.⁴ Obstructive sleep apnea is the most common type — in the U.S. alone, more than 83 million adults are living with OSA.⁵

Not all types of sleep apnea are the same. When you're diagnosed with this condition, your doctor will measure severity using main tool.

• Sleep study: This test measures your breathing, heart rate and blood oxygen levels while you sleep.⁶

Many people don’t realise that they have sleep apnea. In fact, more than 80% of people with obstructive sleep apnea are undiagnosed.⁸ If you think you might be in this group, it's a good idea to talk to your doctor about your sleep. Early diagnosis and treatment can help prevent serious health conditions and improve quality of life.

Obstructive sleep apnea (OSA)

Obstructive sleep apnea (OSA) is a condition where breathing repeatedly slows down or stops during sleep. This typically occurs when the muscles in the back of the throat relax, causing the airway to narrow or collapse for short periods of time. These pauses in breathing can last several seconds and may happen many times per hour. Breathing pauses can starve organs of oxygen. When oxygen levels drop, the body feels it. Tissues can weaken, and in severe cases, cells may actually start to die. These pauses also disrupt sleep throughout the night — even if a person doesn’t fully wake up. As a result, people with OSA often feel tired, groggy or less focused during the day. ¹ 

OSA symptoms can also be influenced by your sleeping position. For example, you may experience more breathing pauses when lying on your back. ³³

While OSA is more common in men, anyone can have it. In fact, 202 million women around the world live with this condition.¹⁰ Rates of OSA are particularly high among women after menopause. ¹¹

How body structure can affect OSA 

Certain physical features can make it easier for the airway to narrow or become blocked during sleep. If your body structure affects your airway, you may have a higher risk of obstructive sleep apnea. Examples include:

• Large tongue¹²

• Abnormalities in your face, jaw or skull³¹

• Extra soft tissue in the soft palate¹²

• Deviated septum and other nasal obstructions¹³

• Recessed chin (retrognathia)¹⁴

  
  

Diagnosing OSA

 If your doctor suspects that you have OSA, they may refer you to a sleep specialist. The specialist will review your symptoms and medical history and, if necessary, schedule a sleep test.⁶ A sleep test collects information about your health — including oxygen levels, heart rate, brain waves and breathing patterns — as you sleep. ⁶ 

There are two types of sleep tests that your doctor might prescribe:

• Home sleep test (HST): HSTs can be conveniently completed from the comfort of your own bed, reducing the amount of time you must wait to get tested. Your doctor may recommend a home sleep test if you’re showing symptoms of a sleep disorder and have not been diagnosed with any other chronic medical conditions.³²

• In-lab polysomnography sleep study (PSG): PSGs are usually conducted overnight in a sleep lab, where a trained lab technician can monitor your sleep. Your doctor may recommend an in-lab sleep test if you have a more complex medical history and may benefit from comprehensive sleep monitoring.⁷

A sleep specialist can determine whether you have OSA based on the results of your sleep study.

What is AHI?

Your doctor will classify your obstructive sleep apnea (OSA) as mild, moderate or severe based on your Apnea-Hypopnea Index (AHI). The AHI measures the number of times per hour your breathing pauses while you sleep.

An AHI score includes apneas, which happens when your breathing pauses for at least 10 seconds. It also counts hypopneas, or instances of shallow breathing due to a partially blocked airway.

Your AHI determines the severity of your OSA: ⁷

• AHI 5-14: Mild OSA

• AHI 15-29: Moderate OSA

• AHI 30+: Severe OSA
  
  

Treatments for OSA

Once you have an OSA diagnosis, your doctor will recommend a treatment plan based on your symptoms and sleep study results. Common treatments include:

• Continuous positive airway pressure (CPAP). A CPAP device keeps your airway open by sending a continuous stream of pressurised air into your nose or mouth. CPAP is highly effective and is the most used and understood method for treating sleep apnea. It's drug-free sleep apnea treatment with zero medication-related side effects ¹⁶ and can help reduce symptoms after the first night.^17,18

• Oral appliances: These devices push your lower jaw forward, creating space behind your tongue and preventing airway collapse. They may be an alternative to CPAP if you have mild or moderate OSA.³⁴

• Positional therapy: If you only experience OSA when you sleep on your back, positional therapy devices such as pillows and vibrating alarms may help you sleep on your side.²⁰

 If these treatments do not relieve your symptoms and you have moderate to severe OSA, your doctor may discuss surgery options. These options include:

• Hypoglossal nerve stimulation (HNS), where a surgical implant moves your tongue forward each time you breathe to keep your airway open. ²¹

• Uvulopalatopharyngoplasty (UPPP), which is a procedure where a surgeon removes soft tissue from your throat, including part or all of the tonsils, soft palate and uvula, to help open your airway and reduce blockage.²²

• Maxillomandibular advancement, where your jaws are repositioned to help open up your airway.²³

  
  
  

Central sleep apnea (CSA)

Central sleep apnea (CSA) is a type of sleep apnea that accounts for about 5-10% among people tested in sleep clinics.³⁵ CSA occurs when your brain stops telling your muscles to breathe regularly while you're sleeping. Unlike obstructive sleep apnea, your breathing muscles don't keep working during these pauses. ¹

CSA may be caused by or linked to underlying medical conditions, including stroke, kidney failure and atrial fibrillation. ²⁵ It's common in older adults and people with heart failure, but less connected to risk factors associated with obstructive sleep apnea (OSA), such as obesity.²⁷

Different forms of central sleep apnea (CSA)

There are several different types of CSA:

• Primary CSA: This rare type of CSA doesn't have a clear cause.³⁶

• Cheyne-Stokes breathing. This breathing pattern features alternating periods of fast, deep breaths and slow, shallow breaths. It's common in people with heart failure.³⁶

• Medication-related CSA. Drugs such as opioids or sedatives may affect your breathing control.³⁸

• High-altitude CSA. People who visit or live at altitudes above 2,000 meters may experience CSA because of the low oxygen levels.¹⁵

• Treatment-emergent CSA (TECSA). Formerly known as complex sleep apnea, treatment-emergent central sleep apnea (TECSA) is a breathing condition that can appear after someone starts treatment for obstructive sleep apnea (OSA). Instead of pauses caused by a blocked airway, breathing may slow or stop because the brain doesn’t send the signal to breathe. ³⁷ For many people, TECSA improves over time. If it doesn’t, a doctor may need to review and adjust treatment. Central apneas improved or resolved spontaneously in approximately two-thirds of patients after 90 days of ongoing CPAP therapy.

• CSA is linked to other health issues. Sometimes, CSA occurs with other medical conditions, such as heart disease or stroke.²⁵

Diagnosing CSA

Before your doctor diagnoses you with central sleep apnea (CSA), they'll likely request a sleep test. They may look for signs that differentiate CSA from other sleep-disordered breathing conditions, including: ³⁸

• Breathing muscles that don't work when you stop breathing

• Pauses in breathing despite an open airway

• Unstable or distinctive breathing patterns³⁰

Treatments for CSA  

The treatment for central sleep apnea (CSA) depends on the type and cause. Adaptive servo-ventilation (ASV), a device that uses automatically adjusted levels of pressurised air to stabilise your breathing, is used for many forms of CSA. However, ASV is not appropriate for everyone. It is not recommended for people with certain types of heart failure. That's why it's important to work closely with a doctor to determine the safest treatment option.

Other treatments for CSA include bi-level positive airway pressure (BiPAP) and supplemental oxygen. Your doctor can work with you to determine which CSA treatment might be the best for you. Your doctor may also recommend treatment for any related medical conditions or adjust your medications if your CSA is drug-induced. ³⁶ 

Understanding sleep apnea risk

Certain conditions or lifestyle factors may influence the type of sleep apnea you have.

Understanding your personal risk factors can help you find the right care and support.

Sleep apnea types in special populations

Some people might have a higher risk for specific types of sleep apnea, including:

• Pregnancy-associated sleep apnea. This type tends to be predominantly obstructive sleep apnea (OSA), and the risk can increase with higher age or body mass index (BMI).²⁸

• Neuromuscular disease-related sleep apnea. The complex issues associated with neuromuscular disease, which are conditions that affect the nerves and muscles and how they communicate with each other, can cause mixed apnea.²⁶

• Post-stroke sleep apnea. After a stroke, you may experience symptoms of both obstructive and central sleep apnea, but OSA is more common.³⁹

• Heart failure-associated sleep apnea. About 40% of people with congestive heart failure have central sleep apnea (CSA).²⁴

• Opioid-induced sleep apnea. Opioid use is predominantly associated with CSA but may also increase the risk of OSA.¹⁹

• Altitude-induced sleep apnea. Altitudes above 5,000 meters can cause CSA.¹⁵

How doctors tell different types apart

Doctors can tell the difference between different types of sleep apnea using a few common criteria, such as:

• Breathing patterns. Sleep studies often reveal distinctive breathing patterns, especially in people with CSA.²⁵

• Respiratory effort. People with OSA typically have continued effort to breathe when they stop breathing, while people with CSA do not.

• Response to initial treatments. People with treatment-emergent central sleep apnea (TECSA)may experience CSA symptoms after starting treatment for OSA.²⁹

• Associated symptoms and health conditions. Certain health conditions and symptoms are associated with different types of sleep apnea. For example, OSA often causes snoring and appears alongside conditions such as asthma and COPD.⁹

• Advanced testing. Advanced tests, such as esophageal pressure monitoring, may be used to help doctors tell the difference between OSA, CSA and mixed apnea.⁴⁰

• Overlap with other conditions. When people have symptoms of multiple sleep-disordered breathing conditions, such as OSA and CSA, they may experience mixed apnea.²⁹

  
  

If you've been diagnosed with sleep apnea, you're not alone — millions of people are living with it every day. Understanding the type of sleep apnea you have can help you make sense of your treatment options and feel more confident about your doctor's recommendations.

Considering your treatment options? Explore Resmed’s wide range of CPAP devices and accessories.

References:

1. National Heart, Lung, and Blood Institute. Sleep apnea - what is sleep apnea? NHLBI, NIH. https://www.nhlbi.nih.gov/health/sleep-apnea

2. Sleep Apnea Living With. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health/sleep-apnea/living-with

3. Knauert et al., (2015). Clinical consequences and economic costs of untreated obstructive sleep apnea syndrome. World Journal of Otorhinolaryngology - Head and Neck Surgery. https://doi.org/10.1016/j.wjorl.2015.08.001

4. Benjafield, Adam V., et al. “Estimation of the Global Prevalence and Burden of Obstructive Sleep Apnoea: A Literature-Based Analysis.” The Lancet. Respiratory Medicine, vol. 7, no. 8, Aug. 2019, pp. 687–98. PubMed, https://doi.org/10.1016/S2213-2600(19)30198-5.

5. Sönmez, I. et al., (2025). Unmasking obstructive sleep apnea: Estimated prevalence and impact in the United States. Respiratory Medicine. https://www.sciencedirect.com/science/article/abs/pii/S0954611125004111

6. Sleep Studies. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health/sleep-studies

7. Kapur VK, et al. Clinical practice guideline for diagnostic testing for adult obstructive sleep apnea: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med. 2017;13(3):479-504. https://doi.org/10.5664/jcsm.6506

8. Faria A, Allen AH, Fox N, et al. The public health burden of obstructive sleep apnea. Sleep Sci. 2021;14(3):257-265. https://doi.org/10.5935/1984-0063.20200111

9. Bouloukaki, I., et al. (2022). Overlaps between obstructive sleep apnoea and other respiratory diseases, including COPD, asthma and interstitial lung disease. Breathe (Sheff). https://pmc.ncbi.nlm.nih.gov/articles/PMC9973497/

10. Wimms A, et al. Global prevalence of mild obstructive sleep apnea in females. Sleep. 2023;46(suppl 1):A234. https://doi.org/10.1093/sleep/zsad077.0532

11. Bixler EO, et al. Prevalence of sleep-disordered breathing in women: effects of gender. Am J Respir Crit Care Med. 2001;163(3 pt 1):608-613. https://doi.org/10.1164/ajrccm.163.3.9911064

12. Schwab RJ, et al. Identification of upper airway anatomic risk factors for obstructive sleep apnea with volumetric magnetic resonance imaging. Am J Respir Crit Care Med. 2003;168(5):522-530. https://doi.org/10.1164/rccm.200208-866OC

13. Yeom, S.W. et al., (2021). Association between septal deviation and OSA diagnoses: a nationwide 9-year follow-up cohort study. Journal of Clinical Sleep Medicine. https://pmc.ncbi.nlm.nih.gov/articles/PMC8494085/

14. Jenzer, A., Schlam, M. Retrognathia. National Library of Medicine National Center for Biotechnology Information. (2023) https://www.ncbi.nlm.nih.gov/books/NBK538303/

15. Burgess, K. and Ainslie, P. (2016) Central Sleep Apnea at High Altitude. Advances in Experimental Medicine and Biology. https://pubmed.ncbi.nlm.nih.gov/27343103/

16. Understanding Pap. Division of Sleep Medicine at Harvard Medical School. (2021). https://sleep.hms.harvard.edu/education-training/public-education/sleep-and-health-education-program/sleep-health-education-37

17. Djonlagic I, et al. First night of CPAP: impact on memory consolidation, attention and subjective experience. Sleep Med. 2015;16(6):697-702. doi:10.1016/j.sleep.2015.01.017. https://pubmed.ncbi.nlm.nih.gov/25953301/

18. Before and After CPAP Machine Effects: How Your Body Changes. Sleep Foundation. (2025). https://www.sleepfoundation.org/cpap/before-and-after-cpap-machine-body-changes

19. Freire, C., et al. (2022). Opioids and obstructive sleep apnea. Journal of Clinical Sleep Medicine. https://jcsm.aasm.org/doi/10.5664/jcsm.9730

20. Srijithesh, P.R., et al., Positional therapy for obstructive sleep apnoea. National Library of Medicine National Center for Biotechnology Information. (2019). https://pmc.ncbi.nlm.nih.gov/articles/PMC6491901/

21. Mashaqi S, et al. The hypoglossal nerve stimulation as a novel therapy for treating obstructive sleep apnea: a literature review. Int J Environ Res Public Health. 2021;18(4):1642. https://doi.org/10.3390/ijerph18041642

22. Uvulopalatopharyngoplasty (UPPP). Medline Plus. https://medlineplus.gov/ency/article/007663.htm

23. Zaghi, S., et al., (2016). Maxillomandibular Advancement for Treatment of Obstructive Sleep Apnea: A Meta-analysis. JAMA Otolaryngol Head Neck Surgery. https://pubmed.ncbi.nlm.nih.gov/26606321/

24. Müller, M., et al. (2010). Central sleep apnoea syndrome in chronic heart failure: an underestimated and treatable comorbidity. Netherlands Heart Journal. https://pmc.ncbi.nlm.nih.gov/articles/PMC2871747/

25. Rana, A, Sankari, A. (2023). Central Sleep Apnea. National Library of Medicine National Center for Biotechnology Information. https://www.ncbi.nlm.nih.gov/books/NBK578199/

26. Aboussouan, L. (2015). Sleep-disordered Breathing in Neuromuscular Disease. American Journal of Respiratory and Critical Care Medicine. https://www.atsjournals.org/doi/full/10.1164/rccm.201412-2224CI

27. Badr, M., et al., (2019). Central Sleep Apnea: a Brief Review. Current pulmonology reports. https://pmc.ncbi.nlm.nih.gov/articles/PMC6883649/

28. Tayade, S. and Toshniwal, S. (2022). Obstructive Sleep Apnea in Pregnancy: A Narrative Review. Cureus. https://pmc.ncbi.nlm.nih.gov/articles/PMC9668203/

29. Noah, W., et al. (2025). Treatment-emergent central sleep apnea resolves with lower inspiratory pressure. Journal of Clinical Sleep Medicine. https://jcsm.aasm.org/doi/10.5664/jcsm.11492

30. Eckert, D., et al. (2007). Central sleep apnea: Pathophysiology and treatment. Chest. https://pmc.ncbi.nlm.nih.gov/articles/PMC2287191/

31. Finke H, et al. Craniofacial risk factors for obstructive sleep apnea: a systematic review and meta-analysis. J Sleep Res. 2023;33(1):e14004. https://doi.org/10.1111/jsr.14004

32. Slowik, Jennifer M., et al. “Obstructive Sleep Apnea.” StatPearls, StatPearls Publishing, 2025. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK459252/

33. Menon A, Kumar M. Influence of body position on severity of obstructive sleep apnea: a systematic review. ISRN Otolaryngol. 2013;2013:670381. https://doi.org/10.1155/2013/670381

34. National Heart, Lung, and Blood Institute. Treatment for sleep apnea. https://www.nhlbi.nih.gov/health/sleep-apnea/treatment

35. Muza RT. Central sleep apnoea: a clinical review. J Thorac Dis. 2015;7(5):930-937. https://doi.org/10.3978/j.issn.2072-1439.2015.04.45

36. MedlinePlus. Central sleep apnea. https://medlineplus.gov/ency/article/003997.htm

37. Zhang J, et al. Treatment-emergent central sleep apnea: a unique sleep-disordered breathing. Chin Med J (Engl). 2020;133(22):2721-2730. https://doi.org/10.1097/CM9.0000000000001125

38. Fodor AC, Huțanu D, Budin CE, et al. Central sleep apnea in adults: an interdisciplinary approach to diagnosis and management—a narrative review. J Clin Med. 2025;14(7):2369. https://doi.org/10.3390/jcm14072369

39. Johnson KG, Johnson DC. Frequency of sleep apnea in stroke and TIA patients: a meta-analysis. J Clin Sleep Med. 2010;6(2):131-137. https://pmc.ncbi.nlm.nih.gov/articles/PMC2854698/

40. Khandoker AH, Karmakar CK, Penzel T, Glos M, Palaniswami M. Investigating relative respiratory effort signals during mixed sleep apnea using photoplethysmogram. Ann Biomed Eng. 2013;41(10):2229-2236. https://doi.org/10.1007/s10439-013-0827-1