Sleep Hypopnea: Definition, Treatment, Causes & More

April 2, 2024 | Casper Editorial Team

Fact checked by Jonathan Eilenberg, CPE

Sleep hypopnea is a sleep-related breathing disorder characterized by slowed, shallow, or restricted breathing that occurs for 10 seconds or longer during sleep. It is often associated with a reduction in airflow of at least 30% and can lead to a decrease in the supply of oxygen to the body.

You’ve probably heard of sleep apnea—a condition characterized by snoring and nighttime bouts of interrupted breathing.1 Sleep apnea is a relatively well-known condition these days, with over 900 million adults affected worldwide,2 but you might not know about sleep apnea’s cousin: sleep hypopnea. 

Sleep hypopnea is a condition in which a temporary, partial obstruction of air occurs during sleep.3 The airway obstruction can be physical, such as a narrowed throat, or the obstruction can be mental, in which your brain interferes with airflow while you sleep.3

Both sleep apnea and sleep hypopnea can cause poor sleep quality and interfere with quality of life, but in this article, we’ll give a much-needed brief on the definition, symptoms, risk factors, and treatment options for sleep hypopnea. 

What is Sleep Hypopnea?

Sleep hypopnea is an under-discussed condition. Many people who suffer from it likely have never even heard the term, but still suffer from its inconvenient symptoms like excessive snoring and daytime drowsiness. Here are a few important things to know about sleep hypopnea:


To understand sleep hypopnea, we should first break down the etymological origin of the word. The word hypopnea derives from the Greek roots hypo-, meaning “low” or “under” and pnoia-, meaning “breath.” Therefore, sleep hypopnea refers to a condition characterized by periods of less-than-optimal breathing during sleep. This is in contrast to apnea, featuring the prefix a-, “without,” implying the absence of breath. 


Sleep hypopnea is defined as a sleep-related breathing disorder characterized by periods of 10 seconds or more during sleep in which someone experiences restricted or overly shallow breathing, with airflow reduced by at least 30% and oxygen saturation reduced by at least 4%.4

Sleep hypopnea differs from sleep apnea in that breathing does not cease completely and the airway is not fully obstructed, but instead takes place at a lower-than-ideal rate due to partial airway obstruction.5 Learn more about the best sleeping positions for breathing problems like sleep apnea and sleep hypopnea in our guide.

The Different Types of Sleep Hypopnea

Sleep hypopnea is not a single uniform condition. Because of the diagnostic criterion of 30% or higher reduced airflow, sleep hypopnea can present in people along a spectrum, from mild to severe, depending on the degree to which airflow is restricted. 

Depending on a person’s amount and kind of airflow restriction, sleep hypopnea falls into three subtypes6:

  • Obstructive sleep hypopnea
  • Central sleep hypopnea
  • Mixed sleep hypopnea

Obstructive Sleep Hypopnea

By far the most common subtype of sleep hypopnea, obstructive sleep hypopnea makes up a whopping 84% of all sleep hypopnea cases.6  It results from a physical blockage of the upper airway. This could be caused by several different factors, including enlarged tonsils or adenoids, obesity, a deviated nasal septum, allergies, or smoking.9

Obstructive sleep hypopnea results in the characteristic symptom of loud snoring because the brain attempts to breathe normally but runs into an obstruction of some sort. If you’ve tried to learn how to stop snoring but nothing seems to work, it could be a sign of obstructive sleep hypopnea.

Central Sleep Hypopnea

Central sleep hypopnea is reduced airflow stemming not from physical airway obstruction but instead from an issue with the brain’s ability to signal the need to breathe.6The “central” in this sleep hypopnea subtype’s name refers to an issue stemming from the central nervous system as opposed to an obstruction somewhere in the airway. 

In central sleep hypopnea, rather than a physical obstruction to the airway being present, the brain is the “obstruction” as it fails to signal air through the lungs. This can come from neurological disorders that interfere with the brain’s ability to send signals during sleep.7

Because the main feature of central sleep hypopnea is a systemic reduction in breath rate, central sleep hypopnea is not usually associated with snoring.7

Mixed Sleep Hypopnea

A not-insignificant portion of sleep hypopneas do not fall neatly into either category, but instead feature both obstruction and a centrally-mediated reduced rate of breathing.6  

Mixed sleep hypopnea can result from someone with a partially obstructed airway who also experiences central nervous system blockage, interfering with the brain’s ability to signal breath at the correct rate.6  Mixed sleep hypopnea may or may not involve snoring, depending on the degree to which a physical obstruction is implicated in the reduced airflow.

Symptoms of Sleep Hypopnea to Watch Out For

How do you know if you have sleep hypopnea? Now that you’re equipped to understand the nuances of this condition, you may be wondering if you might be dealing with sleep hypopnea yourself. Here are a few symptoms to watch out for8:

  • Excessive daytime sleepiness – Sleep hypopnea can cause interrupted sleep, as many people wake up to catch their breath without even realizing it. This can result in being tired during the day, even if you think you’ve had a full night’s sleep. 
  • Loud snoring – As discussed earlier, only obstructive and mixed sleep hypopneas are associated with loud snoring. However, because these two sleep hypopnea subtypes make up more than 90% of diagnoses, it’s possible that people diagnosed with sleep hypopnea may snore at least some of the time. Snoring results from physical obstruction causing reduced airflow.
  • Brain fog or trouble concentrating – If you recall the diagnostic criteria for sleep hypopnea, one of the factors is a 4% or greater reduction in blood oxygen concentration. Suboptimal levels of oxygen being delivered to the brain can impair cognitive function.

It is important to note that simply showing symptoms of sleep hypopnea does not qualify as a diagnosis. In order to pursue treatment, you should pursue a diagnosis from a qualified medical professional in sleep medicine. In the section below, we will discuss what the diagnostic procedure would look like if you are interested in pursuing an official medical diagnosis for your condition. 

Getting Diagnosed for Sleep Hypopnea

Because the diagnostic criteria for sleep hypopnea are so specific, symptoms alone are not enough reason for a sleep doctor to diagnose you. To determine if a patient is in fact experiencing a 30% or greater reduction in airflow and a 4% or greater blood oxygen desaturation during sleep, a doctor will often perform a sleep study.

In a sleep study, you would be asked to spend the night in a sleep lab. During this overnight stay, you would sleep attached to a number of sensors that measure heart rate, blood oxygenation, and your vital signs more broadly. If the clinical results match up with the definition of sleep hypopnea or sleep apnea, you would then be able to receive a more defined diagnosis. 

Risk Factors of Sleep Hypopnea

Sleep hypopnea can affect anyone, but certain genetic and lifestyle factors can significantly increase both the risk of developing this condition and the severity of it. Some of these risk factors include7:

  • A family history of sleep apnea or sleep hypopnea
  • Obesity
  • Smoking
  • Certain neurological conditions (for central sleep hypopnea)
  • Being over the age of 50
  • Regular alcohol use
  • Heart issues or congestive heart failure
  • Enlarged tonsils or adenoids (for obstructive sleep hypopnea)

The Importance of Seeking Treatment for Sleep Hypopnea

Sleep hypopnea can cause interrupted sleep and tiredness. These can range from mild to serious symptoms that detract from quality of life. What’s more, it can cause problems for your partner due to sleep hypopnea’s propensity to cause loud snoring. But left untreated, sleep hypopnea can cause more than sleepless nights. 

Sleep hypopnea (and sleep-related breathing disorders in general) have been implicated in a number of high-risk health conditions. Quality sleep is an important contributor to immune and cardiovascular health, so any sleep disordered breathing condition that significantly interrupts can have severe consequences downstream such as9:

  • High blood pressure
  • Liver issues
  • Diabetes
  • Increased risk of heart attack
  • Increased risk of stroke

Given these potential complications, seeking treatment is advised for anybody with a sleep hypopnea diagnosis. Treatment could include CPAP therapy, which uses a continuous positive airway pressure (CPAP) machine, a device that uses gentle pressure to ensure the airways stay open during sleep. 

Alternatively, an individual with sleep hypopnea could pursue lifestyle changes that would reduce their risk factors for nocturnal airway obstruction. These could include8:

  • Losing weight
  • Quitting smoking
  • Reducing alcohol consumption
  • Optimizing your sleep hygiene

Lastly, for obstructive sleep hypopnea caused by enlarged tonsils or adenoids, a surgical option may be recommended in order to remove the inflamed tissue, open the airways manually, or remove blockages causing the airway restriction.8

Addressing the root causes of sleep-related breathing disorders like sleep hypopnea as early as you can is important not just for your restfulness, but for your overall health. Even without considering the long-term negative effects of sleep hypopnea, addressing this condition can result in a tremendous increase in immediate quality of life. From increased energy to elevated mood throughout the day, the benefits of improving your sleep quality cannot be overstated. 

Better sleep can be obtained from treating sleep disorders, but that’s not the only way. At Casper, our science-backed sleep products are guaranteed to help you rest easy.

Find Restful Sleep with Casper

Once you’ve taken the steps to either rule out or remedy sleep hypopnea as the cause of your sleep trouble, why not go the extra mile to get the best sleep of your life and explore our extensive offerings at Casper? 

From an innovative line of mattresses to incredibly comfortable, breathable sheets to some of the softest, most breathable pillows on the market, Casper has all the products you could possibly need for the perfect night of sleep.

Between convenient advantages like free shipping and flexible financing options, there’s no reason not to give Casper’s line of advanced sleep technology a try. All of our products are rigorously and scientifically tested to help you sleep your best, no matter your unique sleep needs. 


  1. Mayo Clinic. Sleep apnea.
  2. National Council on Aging. Sleep Apnea Statistics and Facts You Should Know.
  3. American Academy of Sleep. AASM clarifies hypopnea scoring criteria.
  4. Journal of Clinical Sleep Medicine. Effect of Varying Definitions of Hypopnea on the Diagnosis and Clinical Outcomes of Sleep-Disordered Breathing: A Systematic Review and Meta-Analysis.
  5. CHEST: Official Publication of the American College of Chest Physicians. What is Hypopnea, Anyway?
  6. Science Daily. Mayo Clinic Discovers New Type Of Sleep Apnea.
  7. Dental Sleep Medicine. Hypopnea.
  8. Sleep Foundation. What is Hypopnea?
  9. Annals of Medical and Health Sciences Research. Obstructive Sleep Apnea Hypopnea Syndrome.