Written by
Eric Suni, Staff Writer
Medically Reviewed by
Dr. Abhinav Singh, Sleep Physician
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Sleep apnea is a sleep disorder marked by abnormal reductions in breathing while a person is asleep. These disruptions reduce the quality of sleep and, if left untreated, can lead to potentially serious health consequences.
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.
Sleep apnea is a type of sleep-related breathing disorder, a group of sleep disorders characterized by abnormal breathing patterns during sleep.
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.
There are several types of sleep apnea, categorized by the cause of breathing disruptions.
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 (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.
The symptoms of sleep apnea include the effects of abnormal nighttime breathing, as well as the daytime effects of reduced sleep quality.
Frequent symptoms of obstructive sleep apnea include:
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.
The symptoms that are most often associated with central sleep apnea include:
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.
The cause of breathing disruptions differs between obstructive sleep apnea and central 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.
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.
Multiple factors affect a person’s chances of developing sleep apnea, and those factors are different for OSA and CSA.
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.
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.
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.
In rare cases, central sleep apnea occurs without any clear cause or underlying medical explanation. When this occurs, it is known as primary or idiopathic central sleep apnea.
Sleep apnea must be diagnosed by a doctor or sleep specialist, and there are several steps in the diagnostic process.
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.
An at-home sleep study for obstructive sleep apnea is an option for certain patients who are believed to have more severe OSA. Taking an at-home sleep apnea test may be more convenient, but the results must still be interpreted by a health professional. Home testing is not used for central sleep apnea.
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.
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:
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.
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.
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.
As in adults, snoring is common for children with obstructive sleep apnea. However, children may have other nighttime symptoms like sweating, bedwetting, or sleepwalking. Children with severe untreated OSA may also experience problems with their growth and development.
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.
Practical steps can help people living with sleep apnea to cope with this condition and its potential health effects.
Staff Writer
Eric Suni has over a decade of experience as a science writer and was previously an information specialist for the National Cancer Institute.
Sleep Physician
MD
Dr. Singh is the Medical Director of the Indiana Sleep Center. His research and clinical practice focuses on the entire myriad of sleep disorders.
