Conditions guide

Sleep Apnea

Sleep apnea is a common sleep disorder in which breathing repeatedly stops or becomes very shallow during sleep. These pauses disrupt sleep and can lower oxygen levels, and the condition often goes unrecognized.

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At a Glance

  • Obstructive sleep apnea, caused by the airway narrowing or closing during sleep, is the most common type.
  • Loud snoring, gasping or choking at night, and daytime sleepiness are common signs.
  • Bed partners often notice pauses in breathing before the person with sleep apnea does.
  • Diagnosis is made with a sleep study, done in a sleep lab or at home.
  • Untreated sleep apnea is linked with high blood pressure, heart disease, stroke, and drowsy driving.
  • Positive airway pressure (CPAP) is a widely used and effective treatment.

What It Is

In obstructive sleep apnea (OSA), the muscles in the throat relax during sleep, allowing soft tissues to narrow or block the upper airway. Breathing slows or stops for a short time until the brain briefly wakes the person to reopen the airway, often with a snort or gasp. This can happen many times an hour, usually without the person remembering it.

Central sleep apnea is less common. It happens when the brain does not send consistent signals to the muscles that control breathing. It can be linked to heart failure, stroke, certain medicines such as opioids, or high altitude. Some people have features of both types.

Because sleep is repeatedly interrupted, people with sleep apnea often feel unrefreshed even after a full night in bed. Over time, the repeated drops in oxygen and stress on the body can affect the heart, blood vessels, and metabolism.

Common Terminology

Apnea
A pause in breathing lasting at least 10 seconds during sleep.
Hypopnea
A period of shallow breathing during sleep that reduces airflow and is often linked with a drop in oxygen or a brief awakening.
Apnea-hypopnea index (AHI)
The average number of apneas and hypopneas per hour of sleep, used to describe severity.
CPAP
Continuous positive airway pressure, a machine that delivers steady air pressure through a mask to keep the airway open during sleep.
Polysomnography
An overnight sleep study that records breathing, oxygen levels, brain waves, heart rhythm, and movement.
Oxygen desaturation
A drop in the amount of oxygen in the blood, which can occur during breathing pauses.

Common Causes and Associations

Several factors can make the airway more likely to narrow during sleep or affect breathing control.

  • Excess body weight, especially around the neck, is a leading risk factor for obstructive sleep apnea.
  • A naturally narrow airway, large tonsils or adenoids, a large tongue, or a small or recessed jaw can contribute.
  • Obstructive sleep apnea is more common in men and becomes more common with age; risk in women increases after menopause.
  • Alcohol, sedatives, and some sleep medicines relax throat muscles and can worsen apnea.
  • Smoking and nasal congestion are associated with higher risk.
  • Family history may play a role.
  • Heart failure, stroke, and opioid medicines are associated with central sleep apnea.

Symptoms and Features

This is a general description, not a diagnostic checklist. Not everyone with sleep apnea snores, and not everyone who snores has sleep apnea.

  • Loud, frequent snoring.
  • Pauses in breathing during sleep noticed by another person.
  • Waking up gasping, choking, or short of breath.
  • Excessive daytime sleepiness or falling asleep during quiet activities.
  • Morning headaches or a dry mouth or sore throat on waking.
  • Trouble concentrating, memory problems, irritability, or low mood.
  • Waking often during the night to urinate.

Tests and Evaluation

A sleep study is the main way sleep apnea is diagnosed and its severity measured.

  • A clinician reviews sleep habits, symptoms, and any reports from a bed partner, sometimes using questionnaires about sleepiness.
  • A physical exam may look at the neck size, mouth, throat, nose, and jaw.
  • In-lab polysomnography records breathing, oxygen, brain activity, heart rhythm, and movements overnight.
  • Home sleep apnea testing uses a simpler portable device and is often used when obstructive sleep apnea is suspected in otherwise healthy adults.
  • Results are often summarized with the AHI, with severity generally described as mild (5 to 14 events per hour), moderate (15 to 29), or severe (30 or more) in adults.
  • Additional evaluation may look for related conditions such as high blood pressure or heart rhythm problems.

Treatment Overview

Treatment depends on the type and severity of sleep apnea and is chosen with a clinician.

  • Positive airway pressure (such as CPAP or auto-adjusting PAP) is a common and effective treatment for obstructive sleep apnea.
  • Oral appliances, fitted by a dentist, can move the jaw or tongue forward to help keep the airway open in some people.
  • Weight loss can reduce severity in people with overweight or obesity, and certain weight-loss medicines have been approved for obstructive sleep apnea with obesity.
  • Sleeping on the side rather than the back can help when apnea is worse in that position.
  • Avoiding alcohol and sedatives near bedtime is often advised.
  • Surgery, such as removal of tonsils, airway procedures, or an implanted hypoglossal nerve stimulator, may be considered for selected people.
  • Central sleep apnea treatment often focuses on the underlying condition and may use specialized airway pressure devices.

When Professional Care May Be Discussed

Sleep-related symptoms are commonly discussed with a primary care clinician or a sleep specialist.

  • Loud snoring with observed breathing pauses or gasping is commonly evaluated by a healthcare professional.
  • Daytime sleepiness that affects work, school, or driving is generally considered a reason for evaluation.
  • People with high blood pressure that is hard to control, atrial fibrillation, heart failure, or stroke are often screened for sleep apnea.
  • Trouble tolerating a CPAP mask or machine is typically discussed with the care team, since adjustments are often possible.
  • Drowsiness while driving is generally treated as a safety concern that warrants prompt discussion.

Questions to Ask a Healthcare Professional

General questions people often find useful to bring to an appointment:

  • What is the difference between obstructive and central sleep apnea?
  • Is a home sleep test or an in-lab sleep study more appropriate in this situation?
  • What does the AHI number mean, and how is severity described?
  • What treatment options are available besides CPAP?
  • How can CPAP comfort problems, such as mask fit or dryness, usually be addressed?
  • How might sleep apnea relate to blood pressure, heart health, or diabetes?
  • How is the effectiveness of treatment generally checked over time?

Sources

This guide was written in plain language from the following authoritative references.

  1. Sleep Apnea — MedlinePlus (U.S. National Library of Medicine)
  2. Sleep Apnea — National Heart, Lung, and Blood Institute (NHLBI)
  3. Sleep apnoea — NHS

Last updated October 8, 2026. FreeDoc guides are general educational information and are not a substitute for care from a qualified professional.