Obstructive Sleep Apnea Overview

What Happens During an Apnea

During sleep the muscles that hold the throat open relax. In OSA the soft tissue of the throat and the base of the tongue fall back far enough to narrow or block the airway. Breathing effort continues against the blockage, oxygen levels drop, and the brain briefly rouses the sleeper to reopen the airway. Then the cycle starts again.¹

These arousals are usually too brief to remember. Someone with moderate OSA may stop breathing or breathe shallowly 15 to 30 times an hour and wake believing they slept through. The count of events per hour is the apnea-hypopnea index, explained in understanding AHI and REI.¹

Signs and Risk Factors

What others notice. Loud snoring, pauses in breathing, and gasping or choking during sleep. A bed partner is often the first to raise it.¹

What the sleeper notices. Unrefreshing sleep, daytime sleepiness, morning headaches and waking to urinate at night. Some people with OSA have none of these.¹

Who is most at risk. Excess weight is the strongest risk factor. Male sex, older age, a large neck and the shape of the jaw and airway also raise the odds.¹ How weight and the airway interact is covered in weight and sleep apnea.

Why It Goes Unnoticed

The person with OSA is asleep for every episode. Daytime symptoms build slowly and are easy to put down to age, stress or a busy schedule. People who sleep alone may have no witness at all. The American Heart Association describes OSA as under-recognized and undertreated, even in heart clinics where it is most common.⁶

How It Is Diagnosed

Screening. Questionnaires such as STOP-Bang estimate risk. The American Academy of Sleep Medicine’s guideline is explicit that they should not be used to diagnose OSA without a sleep test.³

Home testing. For adults with signs of moderate-to-severe OSA and no complicating conditions, a technically adequate home sleep apnea test is an accepted way to make the diagnosis.³ See home sleep apnea testing.

In-lab testing. Overnight polysomnography records breathing alongside brain activity, oxygen and movement. It is used when home testing is unsuitable or inconclusive.³ See what happens in a sleep study.

Health Effects of Untreated OSA

OSA is common in people with cardiovascular disease. An estimated 40% to 80% of people with high blood pressure, heart failure, coronary artery disease, atrial fibrillation or stroke have it.⁶ Daytime sleepiness from OSA also carries a risk on the road.¹

Treatment, and Why Airway Therapy Usually Comes First

Positive airway pressure. A CPAP or auto-adjusting device keeps the airway open with gentle air pressure through a mask. The AASM strongly recommends it for adults with OSA and excessive sleepiness.⁴ It works only while it is worn, and the guideline recommends education and practical support when starting it.⁴

Other airway treatments. Oral appliances that hold the jaw forward, surgery to the airway, and hypoglossal nerve stimulation for selected patients. Weight loss and exercise also reduce severity.¹

Tirzepatide. In December 2024 the FDA approved tirzepatide (Zepbound) as the first medication for moderate-to-severe OSA in adults with obesity, coupled with lifestyle changes.⁵ The two year-long trials behind that approval enrolled people with moderate-to-severe sleep apnea, averaging about 50 breathing events an hour, well into the severe range.^1,7 Most people on tirzepatide, 61% to 72%, cut their breathing events by at least half, against 19% to 23% on placebo.⁷ The trials also measured positive effects beyond the event count, including blood pressure reduction, a reduction of an inflammation biomarker, and less oxygen loss overnight. Participants also reported less disturbed sleep and less daytime impairment.⁷

By the end, 42% to 50% had no sleep apnea, or only mild sleep apnea without significant daytime sleepiness, against 14% to 16% on placebo.⁷ Although tirzepatide does not result in the same reduction of breathing events per hour as CPAP, it represents a clinically significant improvement.^1,5,7 For adults with obesity, a clinician can evaluate whether it can serve as the primary treatment, particularly for people who have not tolerated CPAP or have not been able to keep using it. Its label carries a boxed warning about thyroid C-cell tumors seen in rodents, and it is not used by anyone with a personal or family history of medullary thyroid cancer or MEN 2; tirzepatide side effects and safety covers the rest.⁸

Modafinil, for sleepiness that remains. Some people stay sleepy even when airway therapy is working. Modafinil is FDA-approved to improve wakefulness in adults with excessive sleepiness associated with OSA. It treats the sleepiness, not the obstruction, and its label calls for airway therapy to continue alongside it.⁹ Headache is its most common side effect; modafinil side effects and safety covers rare serious rashes and the interaction with hormonal birth control.⁹

Getting Evaluated

Loud snoring, pauses in breathing that someone has noticed, or unrefreshing sleep despite enough time in bed are reasons to be evaluated. An evaluation reviews your symptoms and history and sets out the testing that fits. A screening questionnaire alone does not confirm OSA, and treatment depends on what testing shows. Not every evaluation ends in a prescription.

If you already have a diagnosis and remain sleepy despite using airway therapy, an evaluation can look at that leftover sleepiness.