Understanding the Types of Sleep Apnea
Pauses in breathing during sleep can be dangerous
Medically reviewed by Smita Patel, DO
Sleep apnea is a medical condition that causes a person to stop breathing during sleep. Of the different types of sleep apnea, obstructive sleep apnea (OSA) is the most common. It’s estimated that approximately 20% of adult males and 10% of postmenopausal women experience OSA.
OSA is caused by a recurrent blockage of the upper airways during sleep. Central sleep apnea (CSA), which is far less common than OSA, occurs when the brain’s control of breathing is disrupted during sleep. A combination of these two conditions are known as mixed sleep apnea or complex sleep apnea.
The interrupted sleep caused by sleep apnea can prevent you from getting adequate rest, resulting in excessive sleepiness, headaches, and daytime fatigue. Sleep apnea is also dangerous for your health and has been associated with medical complications, such as heart disease.
It’s important to know that sleep apnea can be accurately diagnosed, and the treatment can help you get adequate sleep and avoid health complications. This article will detail the three types of sleep apnea and their causes, risk factors, symptoms, diagnosis, and treatment.
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Obstructive Sleep Apnea (OSA)
Since OSA is the most common form of sleep apnea, you might receive a diagnosis of "sleep apnea" if you have OSA.
Usually, OSA can occur if the muscles that hold open the upper airways become excessively relaxed during sleep. Enlarged tissue around the upper airway—such as large tonsils—can sometimes contribute to OSA. You can experience symptoms and effects of OSA if you have episodes of upper airway blockage during sleep but not during wakefulness.
Risk factors for OSA include:
Obesity
Enlarged tonsils
Hormone changes
Aging
Family history
Muscle relaxants
Alcohol, drugs
During sleep, the body’s muscles naturally relax. You may be more prone to upper airway obstruction when your muscles relax during sleep if you have these underlying risk factors.
Most people who have OSA do not notice their own symptoms. The most common symptom of OSA is tiredness and a need for excessive sleep. You may also have headaches due to fatigue and lack of restful sleep.
Snoring
Snoring is a very common symptom of OSA. But it is possible to have OSA without snoring, and most people who snore do not have OSA.
Sometimes others who are around (and awake) may notice that an individual with OSA gasps for breath or has brief pauses in breathing during sleep. A spouse or roommate most commonly notices this symptom.
If you have OSA, you may have pauses in your breathing that last for a few seconds at a time. These pauses can occur many times each night. When your body senses the effects of interrupted breathing, you will typically wake up and begin a regular breathing pattern again—and then fall asleep.
With OSA, you can have episodes that occur tens or hundreds of times per night. Most people who have OSA do not notice these periods of waking up and will not usually open their eyes or interact with others during these moments of catching their breath.
Related: What Causes Mild Obstructive Sleep Apnea?
Diagnosis and Treatment
Sleep apnea is diagnosed with a combination of medical history, evaluation of symptoms and risk factors, and polysomnogram (sleep study).
A sleep study can detect changes during sleep, particularly the sequence and duration of the sleep stages you undergo. The brief periods of wakefulness during sleep that occur with OSA can be recognized with a sleep study. A sleep study can also identify snoring, blood oxygen levels, breathing rates, and muscle movements during sleep.
Several different treatments are available for OSA. These may include lifestyle changes. Sleeping with your head elevated and losing weight can help some people eliminate or reduce episodes of OSA. Additionally, simple treatments can include wearing an oral appliance to help keep the upper airways open.
In some cases, a continuous positive airway pressure (CPAP) device can be used to keep the airways open, preventing breathing interruptions during sleep. These mechanical devices supply mild pressure to the airways, are prescribed by a physician, and can be worn all night.
Very rarely, surgical intervention may be necessary to alleviate obstruction from enlarged tissue covering the upper airway.
Medication for OSA
Provigil (modafinil) is a medication that is Food and Drug Administration (FDA) approved for the treatment of daytime sleepiness. It does not help prevent sleep apnea, but it can be used to treat daytime sleepiness that occurs as a result of sleep apnea.
Central Sleep Apnea (CSA)
A far less common type of sleep apnea, CSA, occurs when the brain’s control of respiratory drive is disrupted during sleep. This condition is very dangerous, because people who have CSA, might not wake up to catch their breath when they stop breathing. This can potentially result in a lack of oxygen to the brain, brain damage, or even death.
Disrupted breathing that causes CSA can occur due to impaired brain development or as a result of brain damage. Regions of the brain that regulate breathing include the brainstem, hypothalamus, and areas of the cerebral cortex.
Congenital (from birth) conditions or brain damage later in life, such as from a stroke, neurodegenerative disease, or head trauma, can interrupt the functions of these areas.
Central sleep apnea is also seen in people who have a Cheyne-Stokes breathing pattern. This disordered breathing pattern is associated with heart failure, stroke, and kidney disease. Heart and kidney disease can also produce central sleep apnea without Cheyne-Stokes breathing.
Opioid medications are also associated with central sleep apnea.
The signs of CSA can vary widely, depending on the severity and underlying cause. In some cases, very young children can be diagnosed at birth or shortly after birth. Sometimes, CSA can be diagnosed through observation during a hospital stay or due to brief drops in oxygen levels during sleep.
Diagnosis and Treatment
Adults or children who have CSA due to brain injuries or disease may be diagnosed based on blood oxygen levels and with the aid of a sleep study.
A CPAP machine may be helpful in the treatment of CSA as a means to prevent interrupted breathing. Sometimes, CSA is treated with bilevel positive airway pressure (BiPAP), which utilizes a device that provides support for inspiration (breathing in) and expiration (breathing out).
Complex Sleep Apnea
Complex sleep apnea is a type of sleep apnea that involves a combination of OSA and CSA. Complex sleep apnea, or mixed sleep apnea, has several variations. You may have a combined type of sleep apnea or you could develop both conditions independently.
Sometimes people who have OSA can develop CSA. The exact mechanism that causes secondary CSA to develop is not completely understood, but research suggests that treatment of OSA may lead to decreased respiratory drive, contributing to CSA.
Additionally, some people may have independent risk factors for both conditions. You may have some features of CSA with significant features of OSA, or you may have some mild upper airway obstruction, even when the main problem is CSA.
The symptoms of mixed sleep apnea may include pauses and breathing during sleep, daytime fatigue, excessive sleep, snoring, and visible shortness of breath during sleep.
Diagnosis and Treatment
It can be difficult for an individual or to differentiate between OSA, CSA and mixed sleep apnea. This complicated diagnosis may emerge during diagnostic testing.
The treatment of mixed sleep apnea is individualized and may involve positive airway pressure, potentially with supplemental oxygen. Monitoring oxygen level and respiratory rate may be part of the treatment.
A Note on Gender and Sex Terminology
Verywell Health acknowledges that sex and gender are related concepts, but they are not the same. To reflect our sources accurately, this article uses terms like “female,” “male,” “woman,” and “man” as the sources use them.
Summary
Sleep apnea is not uncommon, and it can be caused by upper airway obstruction or altered control of breathing that occurs during sleep, but not while awake. This is because some of the mechanisms that keep the airway open and help control breathing are more active during wakefulness and less active during sleep.
Obstructive sleep apnea (OSA) and central sleep apnea (CSA) are the two main types of sleep apnea. Sometimes, people may have a mixed type. The diagnosis of sleep apnea, its severity, its type, and its cause are all important factors in identifying the best treatment plan.
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