Obstructive Sleep Apnea

Obstructive sleep apnea, abbreviated OSA, is a sleep-related breathing disorder in which the upper airway repeatedly narrows or closes during sleep. These breathing disruptions can fragment sleep, lower oxygen levels, and affect how a person feels and functions during the day.

OSA is common, treatable, and often under-recognized. Some people notice loud snoring, gasping, or pauses in breathing at night. Others first notice daytime effects, such as sleepiness, fatigue, morning headaches, difficulty concentrating, irritability, or reduced quality of life.

This page focuses on adult OSA. Children and teens can also have OSA – see Sleep Apnea – Children and Teens.

During sleep, the muscles of the upper airway naturally relax. In people with OSA, the airway becomes narrow or blocked enough to reduce breathing. A partial reduction in airflow is called a hypopnea. A pause in breathing is called an apnea.

The brain usually responds by briefly shifting the person into lighter sleep so breathing can resume. These brief awakenings may not be remembered, but they can happen dozens or hundreds of times per the night, making sleep less restorative.

OSA is different from central sleep apnea. In OSA, the main problem is repeated airway narrowing or blockage. In central sleep apnea, the brain does not send breathing signals consistently during sleep. 

OSA severity is often described using the apnea-hypopnea index, or AHI, which estimates the average number of breathing events per hour.

• AHI <5: not considered clinical sleep apnea
• AHI 5 – 14: mild sleep apnea
• AHI 15-29: moderate sleep apnea
• AHI: 30+: severe sleep apnea

Clinicians also consider daytime symptoms, sleep quality, oxygen levels, and health conditions, because the same AHI number can affect people differently.

OSA symptoms vary – some people have obvious nighttime symptoms, while others notice mostly daytime symptoms. Even if some symptoms are subtle, OSA affects the whole 24-hour day. 

Nighttime symptoms

• Loud, frequent, or disruptive snoring
• pauses in breathing noticed by a bed partner
• gasping, choking, snorting, or coughing during sleep
• restless or fragmented sleep
• frequent awakenings
• waking with a dry mouth or sore throat
• waking suddenly with a sense of breathlessness

Snoring is common, but not everyone who snores has OSA. However, loud snoring with gasping, choking, breathing pauses, or daytime symptoms should be evaluated.

A partner or family member may notice symptoms before the person with OSA does. Their observations can support diagnosis and treatment follow-up.

Daytime symptoms

OSA affects more than breathing during sleep, it causes symptoms across the entire 24-hours. Repeated airway blockage can fragment sleep, lower oxygen levels, and activate stress responses in the body. The next day, this disruption may produce many daytime symptoms, including:

• Brain and cognition: morning headaches, reduced attention, slower processing, memory problems, and difficulty with concentration and decision-making.
• Mood and mental health: excessive daytime sleepiness, fatigue, irritability, low motivation, anxiety or depression symptoms, and reduced stress tolerance.
• Safety: increased risk of drowsy driving, workplace errors, and accidents.Drowsy driving is a serious safety issue, and should prompt evaluation.
• Relationships: disrupted bed partner sleep, concern about breathing pauses, and changes in shared routines.
• Daily structure: more caffeine use, reduced activity, irregular naps, and difficulty maintaining consistent routines.

OSA cannot be diagnosed by symptoms alone. A sleep study is needed to confirm the diagnosis and understand the type and severity of sleep apnea.

Screening tools

Clinicians may use questionnaires to estimate the likelihood of OSA or daytime sleepiness. Examples include the STOP-Bang questionnaire, Epworth Sleepiness Scale, and Berlin Questionnaire. These tools can support decision-making, but they do not replace diagnostic testing. Diagnosis requires a sleep study or at-home sleep apnea test.

Sleep studies

An in-lab polysomnogram is an overnight sleep study performed in a sleep center. It records sleep stages, breathing, blood oxygen saturation levels, heart rhythm, body position, and movements. It can help diagnose OSA and identify other sleep disorders.

A home sleep apnea test is done at home with portable equipment. It usually measures breathing, oxygen levels, heart rate, and breathing effort. It can be appropriate for many adults when there is a strong suspicion of moderate to severe OSA and no major complicating conditions.

If a home test is negative, unclear, or does not match the person’s symptoms, further evaluation may be needed.

How to get help

A primary care clinician is a good first step for diagnosing sleep disorders. For a list of information and questions to bring to an appointment, check out WSCN’s How to talk to your primary care clinician about sleep problems checklist.

Causes and risk factors

OSA can be caused by many factors, and can affect people of any body size, sex, gender, race, or age. Risk is shaped by anatomy, physiology, hormones, health conditions, medications, and environment.

Common risk factors and contributors include:

• Physiological factors: a smaller airway, larger mouth or airway tissues, recessed jaw, large neck circumference, nasal obstruction, or chronic congestion
• Life cycle: older age, hormone changes, menopause, higher body weight*
• Genetics: family history of OSA
• Medication and Substances: sedating medications or opioids, alcohol use
• Positional: sleeping on the back

*Weight can be one contributing factor to developing OSA, but the reverse is also true: OSA can raise cortisol levels in the body, changing the body’s metabolism and promoting weight gain. 

Health implications

Having untreated Obstructive Sleep Apnea can increase the risk of developing a number of serious chronic health conditions, such as:

• Cardiovascular disease: high blood pressure, atrial fibrillation, coronary heart disease, heart attacks, stroke
• metabolic disease: insulin resistance, type 2 diabetes, metabolic syndrome
• alzheimer’s disease

OSA treatment should be individualized. The goals are to improve breathing during sleep, reduce symptoms, support daytime function, lower safety risks, and address related health concerns.

OSA commonly occurs with other health conditions. Treating OSA does not guarantee prevention or reversal of other health conditions, but it can help in some circumstances.

Positive airway pressure therapy

Positive airway pressure, or PAP, is one of the most effective treatments for adult OSA, and is commonly the first treatment prescribed. PAP devices deliver pressurized air through a mask to help keep the airway open during sleep.

Types of PAP may include:

• CPAP: continuous positive airway pressure
• APAP: auto-adjusting positive airway pressure
• BiPAP or bilevel PAP: two pressure levels, used in select situations

PAP can reduce apnea/hypopnea events, improve oxygen levels, reduce snoring, and improve daytime alertness and quality of life for many people.

Some people adjust quickly to PAP and notice immediate relief; others struggle to adjust to PAP therapy. Common challenges include mask leaks, dry mouth or nose, pressure discomfort, skin irritation, claustrophobia, cleaning routines, bed partner concerns, travel concerns, and cost or insurance barriers. However, there are many ways to address these challenges: a different mask, air humidification, pressure adjustment, desensitization practice, nasal treatment, education, or peer support can help make PAP treatment comfortable and effective.

Oral appliance therapy

Oral appliance therapy uses a custom dental device worn during sleep, similar to a sports mouthguard or dental retainer. The most common type moves the lower jaw slightly forward to help keep the airway open; another type prevents the tongue from falling backward to block the airway.

Oral appliances may be considered for adults with mild to moderate OSA, or people who cannot tolerate PAP. A qualified dental sleep medicine provider should fit and monitor the device. Mouthguards available over-the-counter or online are not the same as custom oral appliances for OSA, and usually will not safely or effectively treat sleep apnea.

Positional therapy

Some people have OSA mainly when sleeping on their back. Positional therapy uses pillows or other positioning devices to help the person sleep on their side or avoid back-sleeping. It may be helpful when sleep testing shows that OSA is strongly position-dependent, but it may not be enough for all people.

Weight-related support, when relevant

For some people, weight loss can reduce OSA severity and improve symptoms. Weight-related support may include nutrition care, physical activity, behavioral treatment, anti-obesity medications, or bariatric surgery when clinically appropriate. 

Because OSA can negatively affect a person’s metabolism, it is important to work with a doctor and receive appropriate support when trying to lose weight with OSA. Even after weight loss, many people still need PAP, oral appliance therapy, or another OSA treatment. It is also important to note that not everyone with OSA is overweight.

Surgery and hypoglossal nerve stimulation

Surgery may be considered when anatomy contributes to airway obstruction, when other treatments are not tolerated, or when a specific surgical target is identified. Options may include nasal surgery, tonsillectomy, soft palate procedures, jaw advancement surgery, multilevel airway surgery, or bariatric surgery when clinically appropriate.

Hypoglossal nerve stimulation is an implanted treatment for selected adults with moderate to severe OSA who cannot tolerate PAP and meet specific clinical criteria. It works by stimulating muscles that help move the tongue forward during sleep.

Follow-up sleep testing is often needed after surgery or implanted therapy to assess whether OSA has improved.

Long-term follow-up

OSA treatment often needs adjustment over time. Follow-up may include reviewing symptoms, PAP data, mask fit, oral appliance comfort, weight changes, medications, nasal symptoms, menopause status, and other health conditions. The right treatment is the one that is clinically appropriate and usable in real life.

Living with OSA

Living with OSA can involve adjusting to treatment, talking with family or partners, and navigating insurance, equipment, and follow-up care. To determine how well treatment is working, it can help to track:

• Bedtimes and wake times
• nighttime symptoms like snoring, choking, gasping, or breathing pauses
• daytime symptoms like sleepiness and fatigue, morning headaches, mood, and concentration
• amount of PAP or oral appliance use, and issue with using treatment
• naps, caffeine, medication, and alcohol use

OSA research continues to evolve. Scientists and clinicians are studying why OSA affects people differently, which treatments work best for which patients, and how to improve long-term outcomes.

Areas of active research include OSA subtypes, cardiovascular and metabolic outcomes, PAP adherence, oral appliance and combination therapies, digital monitoring, access to treatment, OSA in women and underdiagnosed groups, and the overlap between insomnia and OSA.