Obstructive Sleep Apnea: Symptoms, Causes and Treatment

Overview

Obstructive sleep apnea (OSA) happens when the muscles that hold your throat open relax too much during sleep. The airway narrows or collapses, breathing becomes shallow (a hypopnea) or stops (an apnea) for 10 seconds or longer, and your brain briefly wakes you to reopen it. This can happen dozens of times an hour without you remembering any of it.

The repeated drops in oxygen and constant micro-awakenings mean sleep is never fully restorative. Many people notice loud snoring, gasping, morning headaches and heavy daytime sleepiness, although some people, especially women, report fatigue, insomnia or low mood instead.

Untreated OSA is linked to high blood pressure, heart disease, atrial fibrillation, stroke, type 2 diabetes and drowsy-driving crashes. The good news is that effective treatments exist, from CPAP and oral appliances to weight loss, newer medication and implanted nerve stimulators, and most people feel noticeably better once their breathing is stable at night.

A 2019 analysis in The Lancet Respiratory Medicine estimated that about 936 million adults aged 30 to 69 worldwide have mild to severe obstructive sleep apnea.

Common symptoms

Loud, frequent snoring
Pauses in breathing, choking or gasping noticed by a bed partner
Waking with a dry mouth or sore throat
Morning headaches
Excessive daytime sleepiness or dozing off while reading, watching TV or driving
Unrefreshing sleep even after a full night in bed
Waking up often to urinate at night
Trouble concentrating, poor memory or irritability
Waking up with a racing heart or a sensation of choking

Causes and risk factors

Excess body weight, especially fat around the neck and tongue
Narrow airway, large tonsils, a recessed jaw or a large tongue
Male sex, and in women, the period after menopause
Older age
Family history of sleep apnea
Alcohol, sedatives or opioids that relax throat muscles
Smoking
Nasal congestion or obstruction
Sleeping on your back
Conditions such as high blood pressure, type 2 diabetes, heart failure, hypothyroidism and polycystic ovary syndrome

How it is diagnosed

A clinician usually starts with your sleep history and questionnaires such as STOP-Bang (a screening tool for OSA risk) and the Epworth Sleepiness Scale. These help decide who needs testing, but they cannot diagnose OSA on their own.

Diagnosis requires a sleep study. An in-lab polysomnogram records brain waves, breathing, oxygen, heart rhythm and leg movements overnight. For many adults with a high likelihood of moderate to severe OSA and no major heart or lung disease, a home sleep apnea test that measures breathing and oxygen is an acceptable first step.

Results are reported as the apnea-hypopnea index (AHI), the number of breathing events per hour of sleep. In adults, fewer than 5 is considered normal, 5 to 14 is mild, 15 to 29 is moderate and 30 or more is severe. OSA is diagnosed with an AHI of 15 or more, or an AHI of 5 or more together with symptoms such as sleepiness or related conditions such as high blood pressure.

Treatment options

CPAP or APAP

A machine delivers gentle air pressure through a mask to keep your airway open. It is the most effective and most studied treatment, and auto-adjusting machines (APAP) are widely used.

Oral appliance therapy

A custom mouthpiece made by a dentist moves your lower jaw forward to keep the airway open. It is an option for mild to moderate OSA or for people who cannot tolerate CPAP.

Weight loss

Losing weight can reduce the number of breathing events and sometimes resolves mild OSA.

Tirzepatide (Zepbound)

In December 2024 the FDA approved this weekly injection for moderate to severe OSA in adults with obesity, used alongside diet and exercise.

Positional therapy

Devices or techniques that keep you off your back help people whose apnea occurs mainly when sleeping supine.

Hypoglossal nerve stimulation

An implanted device stimulates the nerve that moves the tongue forward with each breath. It is for selected adults who cannot use CPAP.

Surgery

Procedures on the nose, palate, tonsils or jaw (such as maxillomandibular advancement) can help selected people, particularly those with a clear anatomical cause.

Treating nasal congestion

Managing allergies or a deviated septum can make CPAP more comfortable and improve breathing.

What you can do yourself

Use your CPAP every night and for the whole night, including naps
Avoid alcohol and sedating medicines in the hours before bed
Work towards a healthy weight with your care team
Try sleeping on your side if your apnea is worse on your back
Stop smoking
Keep a regular sleep schedule and aim for at least 7 hours
Do not drive or operate machinery when you feel drowsy

When to see a doctor

A bed partner notices you stop breathing, choke or gasp in your sleep
You feel sleepy during the day despite spending enough time in bed
You have nodded off while driving or nearly had a crash
You snore loudly and have high blood pressure, heart disease, atrial fibrillation or diabetes
Your CPAP feels uncomfortable or you have stopped using it

Frequently asked questions

Can you have sleep apnea without snoring?

Yes. Snoring is the most common sign, but not everyone with obstructive sleep apnea snores loudly, and some people, often women, mainly notice fatigue, insomnia, headaches or low mood. If you are tired despite enough sleep, it is worth asking about a sleep study even if no one has heard you snore.

Is a home sleep test as good as a lab study?

For many adults with a high likelihood of moderate to severe OSA and no major heart, lung or neurological disease, a home sleep apnea test is an accepted way to diagnose it. Home tests can underestimate mild apnea because they do not measure actual sleep, so a negative or borderline result in someone with symptoms often needs an in-lab study.

What do the AHI numbers mean?

The apnea-hypopnea index counts breathing pauses and shallow breaths per hour of sleep. In adults, 5 to 14 is mild, 15 to 29 is moderate and 30 or more is severe. Your CPAP machine also reports a residual AHI, and a number under 5 on treatment generally means the pressure is controlling your apnea well.

Will losing weight cure my sleep apnea?

Weight loss often reduces the severity of OSA and can resolve it for some people, especially those with mild disease. It does not work for everyone because jaw shape, airway size and other factors also play a role. Keep using your prescribed treatment until a repeat sleep study shows it is no longer needed.

Is untreated sleep apnea dangerous?

Over time, untreated moderate to severe OSA is associated with high blood pressure, heart disease, stroke, atrial fibrillation and type 2 diabetes. The daytime sleepiness it causes also raises the risk of motor vehicle crashes. Treatment lowers blood pressure in many people and improves sleepiness and quality of life.