What it is, its risk factors, its health impacts, and how it can be treated
Eric Suni, Staff Writer
Medically Reviewed by
Dr. Abhinav Singh, Sleep Physician
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Sleep apnea is a common disorder in the United States, but often goes undiagnosed because many sleepers are unaware of their nighttime symptoms. Learning about the types of sleep apnea, as well as the symptoms, causes, and treatments, can help people understand this condition and minimize its potential health effects.
People with sleep apnea repeatedly have reductions or pauses in breathing for brief periods while they sleep. Although these lapses cause a person to awaken periodically and reduce sleep quality, sleepers may not fully wake up and remain unaware that their nighttime breathing is abnormal.
Obstructive sleep apnea (OSA) occurs when the airway at the back of the throat becomes constricted or blocked during sleep, which may cause snoring as air is prevented from passing through normally. In response to the airway obstruction, a person usually wakes up, engages the muscles in their throat, and takes several gasps or deep breaths, often accompanied by sounds like snorting or choking.
Obstructive sleep apnea is the most common type of sleep apnea. It is estimated to affect 10% to 30% of adults in the United States but in many cases goes undiagnosed.
Central Sleep Apnea
Central sleep apnea (CSA) involves disruption in the communication between the brain and the muscles that control breathing. As a result, breathing may become shallower and have temporary pauses.
The prevalence of central sleep apnea is low compared to obstructive sleep apnea. It is estimated that less than 1% of people have CSA.
Symptoms of Sleep Apnea
The symptoms of sleep apnea include the effects of abnormal nighttime breathing, as well as the daytime effects of reduced sleep quality.
Loud snoring that is often punctuated by gasping or choking sounds
Headaches in the morning that may persist for several hours after waking up
Dry mouth upon awakening
Restless sleep with periods of wakefulness during the night
Increased need to get up from bed to urinate
Irritability or frustration
Certain symptoms of obstructive sleep apnea may not be immediately noticeable to the person with the condition. For example, abnormal breathing and snoring may only come to a person’s attention after they are observed by a bed partner.
Many of the symptoms of obstructive sleep apnea can also be caused by other health issues, so the condition cannot be diagnosed by symptoms alone.
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As with obstructive sleep apnea, it is normal for people with central sleep apnea to be unaware of their irregular breathing during sleep unless they are pointed out by a bed partner or caregiver.
Causes of Sleep Apnea
The cause of breathing disruptions differs between obstructive sleep apnea and central sleep apnea.
Causes of Obstructive Sleep Apnea
In people with obstructive sleep apnea, the muscles in the back of the throat relax during sleep, reducing space for air to pass through. Snoring occurs as the airway narrows, and when the airway is obstructed, a person fails to get enough oxygen. The lack of oxygen causes partial or complete awakenings in order to restore airflow. These breathing disruptions happen repeatedly during sleep.
Causes of Central Sleep Apnea
Central sleep apnea arises because of problems in how the brain communicates with the muscles responsible for breathing. For people with CSA, a part of the brain called the brain stem fails to properly recognize carbon dioxide levels in the body during sleep. This leads to repeated episodes of breathing that is slower and shallower than it should be.
Risk Factors for Sleep Apnea
Multiple factors affect a person’s chances of developing sleep apnea, and those factors are different for OSA and CSA.
Risk Factors for Obstructive Sleep Apnea
The primary risk factors for obstructive sleep apnea are related to age, sex, body weight, and certain anatomical features of the head and neck area.
Age: The risk of developing obstructive sleep apnea increases with age until a person is in their 60s and 70s.
Sex: Men or people assigned male at birth are generally more likely to have obstructive sleep apnea, especially in the earlier stages of adulthood.
Head and neck anatomy: Obstructive sleep apnea occurs more frequently in people who have specific anatomical features including a larger tongue and a shorter lower jaw.
Body weight: Multiple studies have found a correlation between a higher body mass index (BMI) and an elevated risk of developing obstructive sleep apnea.
Studies have identified associations between various other factors and an increased likelihood of having OSA, but further research is needed to clarify their effect on the development of OSA.
Cigarette smoking: Some research has found a noticeably higher risk of obstructive sleep apnea in people who smoke cigarettes compared to people who have quit or never smoked.
Hormone abnormalities: Hormone conditions like an underactive thyroid or excess production of growth hormone may increase the risk of OSA by causing swelling of tissue near the airway or by contributing to a higher body mass index.
Family history of sleep apnea: There are some indications that a family history of OSA can increase a person’s risk of obstructive sleep apnea, which may relate to anatomical features in the head and neck that are shared among family members.
Nasal congestion: Difficulty breathing through the nose has been linked with a higher likelihood of having OSA.
Using alcohol and some medications: Alcohol and some prescription and narcotic drugs are associated with an elevated risk of obstructive sleep apnea.
Certain medical conditions: People with some medical problems, including several heart and lung conditions, may have a greater tendency to develop OSA.
Risk Factors for Central Sleep Apnea
Central sleep apnea most often occurs as a consequence of another medical problem, such as an infection or injury affecting the brain stem, heart or kidney failure, stroke, or excess growth hormone production. Studies have identified some additional factors that are linked with a heightened risk of central sleep apnea.
Age: People who are over age 65 have a heightened risk of breathing disruptions consistent with central sleep apnea.
Sex: Central sleep apnea is more common in men or people assigned male at birth, which may be related to levels of certain sex hormones.
Use of certain drugs: Chronic use of opioid drugs and some prescription medications can affect breathing and have been associated with a higher risk of CSA.
An evaluation for sleep apnea typically starts with a review of a person’s symptoms and overall health, as well as a physical exam. This is designed to detect signs of sleep apnea and identify risk factors that could contribute to the condition.
Although testing is required to confirm that someone has OSA, the presence of symptoms can factor into the diagnosis and help determine the severity of the condition.
A sleep study is necessary to diagnose obstructive or central sleep apnea. The most dependable kind of sleep study is called polysomnography, which is conducted during an overnight stay at a specialized sleep laboratory.
During polysomnography, multiple sensors are used to track breathing, awakenings, oxygen levels, muscle movement, sleep stages, and other aspects of sleep. An in-clinic sleep study can determine if breathing is abnormal and differentiate between obstructive and central sleep apnea. For OSA, polysomnography may involve either one or two visits to a sleep clinic.
The goal of treatment for sleep apnea is to reduce breathing disruptions and improve sleep. The approach to treatment varies between obstructive sleep apnea and central sleep apnea.
Treatments for Obstructive Sleep Apnea
Positive airway pressure (PAP) therapy is a treatment offered to almost all people with obstructive sleep apnea. PAP therapy keeps the airway open with pressurized air that is pumped from a machine through a hose and a mask worn on the face.
A common type of PAP therapy uses a continuous positive airway pressure (CPAP) device that sends a stream of air that is always set to the same pressure level. Other types of PAP devices, such as bi-level positive airway pressure (BiPAP) and auto-titrating positive airway pressure (APAP), provide variability in the amount of air pressure.
Some types of mouthpieces that hold the jaw or tongue in a specific position are a treatment option for people with certain anatomical features and less severe OSA. These oral appliances often do not improve breathing as much as PAP therapy, but they can reduce snoring and may be preferred by people who have difficulties or discomfort when using PAP devices.
Surgery to remove tissue in the throat and expand the airway can be a treatment option for patients who have tissue obstructing their airway. Another type of surgical treatment requires implanting a device to stimulate a nerve that helps control breathing.
An additional component of treatment for obstructive sleep apnea involves lifestyle changes to help manage symptoms. These suggestions may include:
Reducing BMI by losing weight
Getting regular exercise, which may decrease OSA symptoms even without weight loss
Altering sleeping position to avoid back sleeping
Reducing alcohol consumption
Treatments for Central Sleep Apnea
Treatment for central sleep apnea often focuses on addressing the medical issue causing abnormal breathing. If sleep disruptions are mild, treatment for the underlying cause may be all that is required.
However, if the symptoms of central sleep apnea are persistent or severe, additional treatment may be recommended to improve breathing while also trying to resolve the underlying problem. This may include the use of PAP devices to promote steadier breathing during sleep. Other possible treatments include supplemental oxygen therapy or use of medication that can speed up a person’s breathing.
Complications of Sleep Apnea
Effective treatment can generally prevent or resolve serious complications from sleep apnea, but if the condition is left untreated, it can have far-reaching effects on health and well-being.
Sleep apnea reduces sleep quality, and the effects of poor sleep are compounded by how sleep apnea affects oxygen levels in the body.
Accordingly, obstructive sleep apnea has been associated with a higher risk of a diverse range of health problems, including:
In central sleep apnea, the complications that can occur depend largely on the underlying medical issue causing breathing to be disordered.
Sleep Apnea in Children
Although frequently associated with older adults, sleep apnea can occur in children. In young people, obstructive sleep apnea is much more common than central sleep apnea. It is estimated that 1% to 5% of children have obstructive sleep apnea.
Children with OSA may not experience excessive daytime sleepiness as seen in adults with sleep apnea. Instead, they may exhibit daytime symptoms like hyperactivity, learning difficulties, or behavior problems.
For many children, obstructive sleep apnea is caused by enlarged tonsils and adenoids in the throat, and surgery to remove these tissues may be an option for treatment.
Living with Sleep Apnea
Practical steps can help people living with sleep apnea to cope with this condition and its potential health effects.
Work closely with a doctor: It is important to stay in touch with a primary care doctor or sleep specialist and report any ongoing symptoms, challenges with treatment, or other concerns that may require an adjustment to the plan for managing sleep apnea.
Properly care for treatment devices: Whether using a PAP device or a mouthpiece, cleaning and maintenance can help get the most out of treatment and avoid unwanted side effects.
Avoid high-risk activities: People with sleep apnea should be aware of the risks of daytime sleepiness. Especially for people with untreated sleep apnea, activities like driving or operating heavy machinery should be avoided when drowsy.
Consider changing sleeping position: Although they have not been rigorously studied, special products to avoid back sleeping may help some people reduce their symptoms from obstructive sleep apnea.
Minimize alcohol consumption: Reducing alcohol intake can be a component of the treatment plan for sleep apnea. In people with untreated OSA, even daytime alcohol consumption may exacerbate breathing problems at night.
Inform new doctors about sleep apnea: People with sleep apnea should mention this condition to any new medical providers, especially when planning to start a new medication or undergo surgery.
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Eric Suni has over a decade of experience as a science writer and was previously an information specialist for the National Cancer Institute.