Learning Center: Obstructive Sleep Apnea and Snoring

Last reviewed: October 4, 2026

Introduction

Obstructive sleep apnea (OSA) is repeated narrowing or closure of the throat during sleep. Each event lowers the oxygen level and briefly wakes the brain, usually without the person knowing it. OSA is common, often undiagnosed, and more likely with age, male sex and excess weight. Untreated moderate or severe OSA is linked with daytime sleepiness, motor vehicle crashes, high blood pressure and heart disease. A sleep study makes the diagnosis. Treatment is chosen to fit the person: positive airway pressure (CPAP) is the most effective single treatment when it is used, and oral appliances, weight loss (including newer medications), and several kinds of surgery, including hypoglossal nerve stimulation, are effective alternatives for the right patient. In children, enlarged tonsils and adenoids are the usual cause, and removing them is often curative.

The sections below explain each of these points in more detail, with the most relevant published studies. A numbered reference list is at the end of the page.

What happens during obstructive sleep apnea

The throat (pharynx) is a soft tube with no bone or cartilage to hold it open. While awake, the muscles of the tongue and palate keep it open. During sleep those muscles relax. In some people the airway then narrows enough to cause snoring, and in others it collapses completely.

An apnea is a pause in airflow lasting at least 10 seconds.
A hypopnea is a partial reduction in airflow, with a drop in oxygen or a brief awakening.
The apnea-hypopnea index (AHI) is the average number of apneas and hypopneas per hour of sleep. It is the main measure of severity: 5 to 15 events per hour is mild, 15 to 30 is moderate, and 30 or more is severe in adults [1].

Each event ends with a brief arousal. The arousal restores muscle tone and opens the airway, often with a gasp or snort, but it also fragments sleep and causes a surge of adrenaline, heart rate and blood pressure. Someone with severe OSA may have hundreds of these events a night and remember none of them.

Types of sleep apnea (central vs. obstructive)

Sleep apnea may be obstructive, in which breathing effort continues but air cannot get through a blocked throat, or central, in which the brain briefly stops sending the signal to breathe. A given individual may have neither, either, or both types. This page is about obstructive sleep apnea, which is much more common. Central sleep apnea has different causes (such as heart failure, stroke, and opioid medications) and different treatments.

How common it is

OSA is one of the most common chronic conditions in adults. A 2019 analysis estimated that about 936 million adults aged 30 to 69 worldwide have at least mild OSA, and about 425 million have moderate or severe OSA [2]. In a long-running study of adults in Wisconsin, moderate or severe OSA (AHI 15 or more) was found in about 10% of men aged 30 to 49, 17% of men aged 50 to 70, 3% of women aged 30 to 49, and 9% of women aged 50 to 70 [3]. Most people with moderate or severe OSA have never been diagnosed. An earlier Wisconsin analysis estimated that 93% of women and 82% of men with moderate to severe OSA had not been diagnosed [29].

Risk factors

Excess weight, particularly around the neck. Weight is the strongest modifiable risk factor, and rising obesity rates explain much of the increase in OSA over recent decades [3].
Male sex and age. OSA is more common in men and becomes more common with age [3].
Anatomy. Large tonsils, a long soft palate, a large tongue, a small or set-back lower jaw, and nasal obstruction all narrow the airway.
Alcohol and sedating medications, which relax the throat muscles and blunt the arousals that end each event.

Symptoms

The most reliable sign is a bed partner's report of pauses in breathing, gasping, or choking during sleep. Other common symptoms are loud, habitual snoring, unrefreshing sleep, daytime sleepiness, morning headaches, waking to urinate at night, and poor concentration. Many people, particularly women, report fatigue or insomnia rather than sleepiness. Some people with significant OSA have no symptoms they notice.

Effects of untreated obstructive sleep apnea

In general, the more severe the sleep apnea, the stronger the association with harm.

Sleepiness and driving. People with OSA have a higher rate of motor vehicle crashes. A meta-analysis of crash studies found that drivers with OSA crash more often than drivers without it, with the increase in risk most likely between about 1.2 and 4.9 times [4]. Excessive sleepiness while driving should be discussed with a physician promptly.

High blood pressure. In the Wisconsin cohort, people without hypertension at the start were followed over time. Four years later, those with an AHI of 15 or more had about three times the odds of having hypertension as those with no sleep apnea, after accounting for blood pressure at the start, and the risk rose step by step with severity [5].

Heart disease, stroke and survival. Observational studies link severe untreated OSA with more heart attacks, strokes and deaths. In a Spanish study of men followed for about ten years, untreated severe OSA was associated with roughly three times the rate of fatal and non-fatal cardiovascular events compared with healthy men, while men treated with CPAP had rates similar to the healthy group [6]. Over 18 years in the Wisconsin cohort, severe OSA was associated with about three times the risk of death from any cause [7].

What treatment does and does not prove for the heart. Observational studies cannot show that CPAP itself is what lowers cardiovascular risk, because people who use CPAP may differ in other ways. The largest randomized trial, SAVE, assigned 2,717 people with moderate or severe OSA and established heart or blood vessel disease to CPAP or usual care. CPAP did not reduce heart attacks, strokes or cardiovascular deaths over almost four years. Average CPAP use was only about three hours a night, which may have been too little to show a benefit. CPAP did clearly improve snoring, daytime sleepiness, mood and quality of life [8]. The fair summary is that treatment reliably improves how people feel and function, while a benefit for heart attacks and stroke has not been proven in randomized trials.

In children. Effects include concentration and learning difficulties, irritability, behavior problems such as hyperactivity, poor school performance, daytime sleepiness, bed wetting, and, less often, high blood pressure and poor growth.

Evaluation for obstructive sleep apnea

History and examination. The evaluation begins with symptoms, a bed partner's observations, sleep habits, medical conditions and medications. An otolaryngologist examines the nose, mouth, throat, jaw and neck, often with a thin flexible scope passed through the nose, to look for sites of narrowing.

Screening questionnaires. Tools such as STOP-Bang (snoring, tiredness, observed apneas and high blood pressure, plus BMI, age, neck size and gender) are good at identifying people who are likely to have OSA. In its original study, a high STOP-Bang score identified 93% of patients with moderate OSA and 100% of those with severe OSA, but many people with high scores turned out not to have OSA [9]. A questionnaire can raise or lower suspicion. It cannot make or exclude the diagnosis [10].

Sleep studies. A sleep study is the definitive way to make or exclude the diagnosis [10].

An in-laboratory polysomnogram records brain waves, eye and leg movements, airflow, breathing effort, oxygen level, heart rhythm and body position overnight. It is the most accurate and detailed study, and it can detect other sleep disorders.
A home sleep apnea test records airflow, breathing effort and oxygen at home. It is simpler and less expensive. The American Academy of Sleep Medicine recommends it as an acceptable option for adults with a high likelihood of moderate or severe OSA and no major heart, lung or neurologic disease. Because home tests can underestimate severity, a negative or inconclusive home test in someone with suspected OSA should be followed by an in-laboratory study [10].

Drug-induced sleep endoscopy (DISE). When surgery is being considered, a flexible scope can be used to watch the airway while the patient is under light sedation that imitates sleep. DISE shows where and how the airway collapses (palate, tonsils, tongue base, or epiglottis, and whether the collapse is front-to-back, side-to-side, or circular). This helps match the patient to an oral appliance, positional treatment or the right operation [11]. It is also used to select patients for hypoglossal nerve stimulation, because people whose airway collapses in a circle at the palate were excluded from the main trial [12].

Treatment of obstructive sleep apnea in children

In children, OSA is most often caused by enlarged tonsils and adenoids, and removing them (adenotonsillectomy) is very helpful and often curative. The clinical practice guideline on tonsillectomy in children recommends tonsillectomy for children with OSA documented by an overnight sleep study. It recommends a sleep study before surgery for children younger than two and for those with obesity, Down syndrome, craniofacial abnormalities, neuromuscular disorders, sickle cell disease, or mucopolysaccharidoses, and when the need for surgery is uncertain [25].

Two large randomized trials help set expectations:

CHAT compared early adenotonsillectomy with watchful waiting in 464 children aged 5 to 9 with OSA. After seven months, surgery did not improve attention or executive function on formal testing. It did improve behavior, symptoms and quality of life, and the sleep study normalized in 79% of children after surgery, compared with 46% who improved on their own [26].
PATS studied 459 children aged 3 to 12 with snoring and only mild sleep-disordered breathing. Adenotonsillectomy did not improve executive function at 12 months but did improve behavior, sleepiness, symptoms and quality of life [27].

Taken together, surgery reliably improves sleep, behavior and quality of life, and many children with mild disease also improve over time without surgery. The decision is individual.

Tonsillectomy and Airway Obstruction During Sleep (ENTHealth.org) >>

Treatment of obstructive sleep apnea in adults

There is no single best treatment for everyone. The choice depends on severity, symptoms, anatomy, weight, other medical conditions, and what the person will actually use. Many people do best with a combination.

General measures

Avoiding alcohol near bedtime, avoiding sedating medications where possible, and not smoking are recommended for everyone with OSA. Some people have apnea mainly while lying on their back. For them, devices or simple techniques that keep them on their side can help.

Exercise. Regular exercise improves OSA even with little change in weight. A meta-analysis of exercise trials found that AHI fell by about 6 events per hour on average and daytime sleepiness improved, without a significant change in body weight [13]. The trials were small, so the size of the effect is uncertain.

Weight loss and weight-loss medications

Weight loss reduces the severity of OSA and sometimes resolves it. In the Sleep AHEAD study of adults with obesity and type 2 diabetes, an intensive lifestyle program produced an average weight loss of 10.8 kg (about 24 pounds) at one year, compared with 0.6 kg with diabetes education alone. AHI fell by about 10 more events per hour in the lifestyle group, and about three times as many participants had complete remission of OSA [14].

Newer weight-loss medications have changed this part of treatment. In the SURMOUNT-OSA trials, adults with obesity and moderate or severe OSA who took weekly tirzepatide injections for one year lost about 18 to 20% of their body weight. Their AHI fell by about 25 to 29 events per hour (roughly half), compared with about 5 events per hour on placebo [15]. In December 2024 the U.S. Food and Drug Administration approved tirzepatide (Zepbound) for moderate to severe OSA in adults with obesity, used together with a reduced-calorie diet and more physical activity [16]. These medications are taken long term, have side effects (mainly nausea and other digestive symptoms), and their effect on OSA lessens if weight is regained. They may be used alone or alongside other treatments.

Bariatric surgery is an option for people with severe obesity, and guidelines recommend referral to discuss it for adults with OSA and a BMI of 35 or more who cannot use CPAP [17].

Positive airway pressure (CPAP)

CPAP delivers a steady stream of air through a mask that holds the throat open like an air splint. It works for nearly everyone who wears it, at any severity. The American Academy of Sleep Medicine recommends positive airway pressure for adults with OSA who have excessive sleepiness, impaired sleep-related quality of life, or high blood pressure. Automatically adjusting (APAP) machines can be started at home, and education, behavioral support and remote monitoring improve use [18].

The limitation of CPAP is use. Benefit depends on wearing it through the night, every night. Across two decades of studies, about a third of patients prescribed CPAP do not use it enough, and this rate has not improved despite better equipment [19]. Mask fit, nasal congestion, dryness, claustrophobia and pressure intolerance are common reasons. Many of these problems can be fixed, and an otolaryngologist can treat nasal obstruction that makes CPAP hard to tolerate [28].

Oral appliances (mandibular advancement devices)

An oral appliance is a custom mouthpiece, made by a dentist, that holds the lower jaw and tongue forward during sleep. Guidelines recommend oral appliances for adults with OSA who cannot tolerate CPAP or prefer an alternative, using a custom, adjustable device fitted by a qualified dentist, with a follow-up sleep study to confirm that it works [20].

CPAP lowers the AHI more than an oral appliance does, but people use oral appliances more consistently. In a randomized crossover trial of 126 patients, these effects balanced out. Sleepiness and driving simulator performance improved similarly with the two treatments, neither lowered blood pressure overall, and general quality of life improved more with the oral appliance [21]. Oral appliances work best for mild to moderate OSA. Side effects include jaw and tooth discomfort and, over years, small changes in the bite.

Surgery

Surgery is considered when CPAP and oral appliances fail, are not tolerated, or are not wanted, or when a clear anatomic problem is present. The American Academy of Sleep Medicine recommends that adults with OSA and a BMI under 40 who cannot use or will not accept CPAP be referred to discuss surgical options [17]. Surgery aims either to enlarge the airway or to keep it from collapsing. In surgical studies, success is usually defined as a drop in AHI of at least half and to below 20 events per hour [23]. Surgery more often makes OSA milder than eliminates it.

Nasal surgery. Straightening the septum and reducing the turbinates seldom cures OSA on its own, but in people with nasal obstruction it lowers the pressure CPAP needs and helps people use it more [28].

Tonsillectomy and palate surgery (uvulopalatopharyngoplasty, or UPPP). UPPP removes the tonsils and reshapes the soft palate and uvula to widen the throat. It works best in people with large tonsils and collapse mainly at the level of the palate. In the SKUP3 randomized trial, carefully selected adults who had modified UPPP with tonsillectomy had their AHI cut by about 60% (from 53 to 21 events per hour), compared with about 11% in the group that waited [22]. Adults with very large tonsils may benefit from tonsillectomy alone. Recovery involves one to two weeks of significant throat pain.

Hypoglossal nerve stimulation (Inspire). This implanted device senses breathing and gently stimulates the nerve to the tongue with each breath, moving the tongue forward to open the airway. In the STAR trial, 126 patients who could not use CPAP had a median AHI reduction of 68% at one year (from 29.3 to 9.0 events per hour), with improved sleepiness and quality of life [12]. These results held up at five years, when 75% of patients who had a sleep study met the definition of surgical success [23]. Candidates must have moderate to severe OSA, must not have obesity beyond the device's limits, and must not show circular collapse at the palate on DISE. See the Inspire implant page for details.

Jaw advancement (maxillomandibular advancement, or MMA). MMA moves the upper and lower jaws forward, enlarging the whole airway. It is the most effective sleep apnea operation. In a meta-analysis of 45 studies, AHI fell by about 80% on average, 86% of patients met the definition of surgical success, and 39% had their OSA resolved entirely (AHI under 5) [24]. It is a larger operation, with a longer recovery, temporary numbness of the lip and chin, and a change in facial appearance.

Tracheostomy bypasses the throat entirely and cures OSA, but it is reserved for the rare patient with severe, life-threatening OSA who cannot be treated any other way.

Medications

No medication other than tirzepatide is approved to treat the airway collapse of OSA itself. Several drug combinations that increase throat muscle tone during sleep are under study.

Go to treatments for adult OSA >>

Choosing a treatment

Each treatment has a place. In brief:

CPAP works at any severity and is the most effective treatment when it is used. Its limitation is that many people cannot use it every night.
An oral appliance suits mild to moderate OSA and people who cannot tolerate CPAP. It is less effective in severe OSA and can cause jaw discomfort and bite changes.
Weight loss, including tirzepatide, suits people with OSA and obesity. It is a long-term commitment, and the benefit fades if weight is regained.
UPPP and tonsillectomy suit people with large tonsils and collapse at the level of the palate. Recovery is painful, and results are poorer when the tongue base collapses.
Hypoglossal nerve stimulation suits moderate to severe OSA when CPAP has failed and the DISE pattern is favorable. It is an implanted device with strict candidacy rules.
Maxillomandibular advancement suits severe OSA, a small jaw, or failure of other treatment. It is major surgery and changes facial appearance.

Treatment options for snoring

Snoring is vibration of the soft tissues of the throat. Simple snoring, without apneas, is not known to carry the health risks of OSA, but it can disturb a bed partner's sleep, and snoring should be evaluated to make sure OSA is not present. Treatments include weight loss, avoiding alcohol at night, sleeping on the side, treating nasal obstruction, oral appliances [20], and procedures that stiffen the soft palate.

Treatment options for adults with snoring (ENTHealth.org) >>

Summary

Obstructive sleep apnea is repeated collapse of the throat during sleep. It is common, and most people who have it have not been diagnosed.
Moderate and severe OSA are linked with sleepiness, crashes, high blood pressure and heart disease. Treatment clearly improves sleepiness and quality of life; a benefit for heart attacks and stroke has not been proven in trials.
A sleep study, in the laboratory or at home, makes the diagnosis. A questionnaire alone cannot.
CPAP is the most effective treatment when used. Oral appliances, weight loss and tirzepatide, and surgery, including hypoglossal nerve stimulation and jaw advancement, are effective alternatives for the right patient.
In children, removing the tonsils and adenoids is the usual treatment and is often curative.

References

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