Sleep apnea is a common condition in which your breathing stops and restarts many times while you sleep, which can stop your body getting enough oxygen (NHLBI). The usual signs are loud snoring, gasping or pauses in breathing at night and sleepiness during the day. It is diagnosed with a sleep study, either at home or in a sleep lab, and it is treatable: breathing devices such as CPAP and lifestyle changes are the most common treatments. This guide walks through the whole path in order: what it is, how it shows up, who gets it, how to get tested, what the results mean and where to go next.
Not a diagnosis. Only a sleep study read by a clinician can confirm sleep apnea. Questionnaires and online tools can show whether you should ask for a test, but they cannot rule it in or out.
What Is Sleep Apnea?
An apnea is a short pause in breathing. In sleep apnea these pauses happen again and again through the night. When breathing stops, your brain and body become short of oxygen and you may briefly wake up. This may happen a few times a night or, in more severe cases, several hundred times a night (AASM Sleep Education). Pauses can last from a few seconds to minutes (MedlinePlus). Because the wake-ups are so brief, most people do not know it is happening; usually a bed partner or family member hears it first (MedlinePlus).
Obstructive Sleep Apnea (OSA)
Obstructive sleep apnea is the most common type. It happens when your upper airway becomes blocked many times while you sleep, which reduces or completely stops airflow (NHLBI). The muscles of the upper airway relax when you fall asleep, and if you sleep on your back, gravity can pull the tongue backward and narrow the airway further. Air squeezing through the narrowed space makes the tissue vibrate, which is why loud snoring is so common with OSA (AASM).
Central Sleep Apnea (CSA)
Central sleep apnea is less common. The airway is not blocked; instead the brain does not send the right signals to breathe, so the effort to breathe drops or stops (AASM). It is usually linked to a problem in the brain or heart, such as heart failure or stroke, and certain medicines, especially opioid pain medicines, can cause the same breathing pattern (AASM; NHLBI). Sleeping at high altitude can also trigger a form of central apnea that often improves after coming back down (AASM).
| Obstructive sleep apnea | Central sleep apnea | |
|---|---|---|
| What goes wrong | The upper airway collapses or is blocked | The brain does not send the signal to breathe |
| How common | The most common type | Less common |
| Snoring | Loud snoring is the most common symptom | Not the main feature; disrupted sleep and waking short of breath are more typical |
| Typical links | Excess weight, large neck, large tonsils or tongue, recessed jaw, alcohol | Heart failure, stroke, some neurological conditions, opioid use, high altitude |
| Usual first treatment | CPAP; oral appliance for some | PAP therapy and treating the underlying cause |
Sources: NHLBI, NHLBI causes, AASM (OSA), AASM (CSA).
What Are The Symptoms Of Sleep Apnea?
Sleep apnea shows up in two places: in the bedroom, where someone else usually notices it, and in the daytime, where you feel the effects of broken sleep.
At Night
- Loud or frequent snoring, often interrupted by a silent pause and then a snort or gasp (MedlinePlus)
- Breathing that starts and stops, or choking and gasping sounds (NHLBI)
- Waking often during the night to urinate (NHLBI)
- Restless or unrefreshing sleep, and in some people insomnia (AASM)
- With central apnea: frequent awakenings and waking up short of breath (AASM)
During The Day
- Feeling tired or unrefreshed even after a full night in bed, and daytime sleepiness that can affect learning, focus and reaction time (AASM; NHLBI)
- Morning headaches and a dry mouth (NHLBI)
- Trouble concentrating, memory problems and irritability (AASM)
- Lower sex drive or erection problems (AASM)
- Dozing off while reading or watching TV, or feeling sleepy while driving (MedlinePlus)
Symptoms are not the same for everyone. NHLBI notes that loud snoring is more commonly reported by men, while fatigue, headache and insomnia are more commonly reported by women (NHLBI). Children with sleep apnea may be overactive, wet the bed, have worsening asthma or have trouble paying attention at school (NHLBI).
Snoring on its own does not mean you have sleep apnea. Snoring is more likely to be a sign of it when it is followed by silent pauses and choking or gasping sounds (AASM). Our guide to snoring causes and solutions covers simple snoring; for how apnea compares with insomnia, narcolepsy and other conditions, see signs you have a sleep disorder.
Who Is At Risk Of Sleep Apnea?
Excess body weight is the major risk factor for obstructive sleep apnea, although slim people can have it too (AASM). Other factors that raise the risk include:
- Neck size: 17 inches (43 cm) or more for men, 16 inches (41 cm) or more for women (MedlinePlus).
- Airway and face shape: large tonsils or tongue, a small or recessed lower jaw, a deviated septum or nasal polyps (AASM; NHLBI).
- Age and sex: risk rises with age, and sleep apnea is more common in men; in women the risk rises with menopause (NHLBI; AASM).
- Family history: sleep apnea can run in families, partly because genes shape the skull, face and airway (NHLBI).
- Alcohol, sedatives and smoking: alcohol relaxes the throat muscles, sedating medicines can lengthen pauses, and smoking inflames the upper airway (NHLBI; AASM).
- Health conditions: high blood pressure is common in people with sleep apnea, and hormone conditions such as PCOS, low thyroid levels or high growth hormone raise the risk, as do heart or kidney failure (AASM; NHLBI).
For central sleep apnea, the main risks are heart failure, stroke, conditions such as ALS and myasthenia gravis, long-term opioid use, older age and male sex (NHLBI). Because weight is so central to OSA, we cover the two-way link separately in sleep apnea and weight gain.
Should You Get Screened?
If someone tells you that you snore or gasp for air in your sleep, or you are very sleepy during the day, talk to your healthcare provider (NHLBI). Screening questionnaires can help you decide whether to raise it. The best known is STOP-Bang, which doctors use to estimate the risk of OSA before a sleep study; we explain how it works and how accurate it is in why doctors recommend the STOP-Bang questionnaire.
Want a quick read on your own risk before you see someone? Try our sleep apnea risk calculator. If you are not sure apnea is the problem, the sleep disorder probability calculator looks across several common sleep disorders at once.
Keep the limits in mind. The AASM recommends that questionnaires, clinical tools and prediction formulas not be used to diagnose OSA without a sleep study (Kapur and colleagues, 2017). A screening score tells you whether to ask for a test; it does not replace one. Phone apps and sleep trackers may also claim to detect sleep apnea, but their results can be unreliable, so discuss them with your provider (AASM).
How Is Sleep Apnea Diagnosed?
Your provider will ask about your symptoms, risk factors and family history, examine your mouth, neck and throat, and may ask a bed partner whether you snore or choke at night (NHLBI; MedlinePlus). Keeping a sleep diary for two weeks helps (AASM). They may order blood tests for thyroid problems or PCOS, ask about opioid use, and ask whether you have recently been at altitudes above 6,000 feet (NHLBI). Confirming the diagnosis needs a sleep study, which can be done at home or in a sleep lab (MedlinePlus).
Home Sleep Apnea Test vs In-Lab Sleep Study
| Home sleep apnea test | In-lab sleep study (polysomnography) | |
|---|---|---|
| Where | Your own bed; you attach the sensors yourself | Overnight at a sleep center, hospital or hotel-style room with a technologist |
| What it records | Breathing and blood oxygen; some devices add heart rate | Brain waves, eye, chin and leg movement, heart rate, breathing and oxygen |
| Best suited to | Adults highly likely to have moderate to severe OSA and no other significant medical conditions | Complex cases, suspected central apnea or other sleep disorders, and anyone who should not test at home |
| Not suitable when | Low risk of apnea, another sleep disorder suspected, lung, neuromuscular or heart failure conditions | Rarely unsuitable; it gives the most complete picture |
| If the result is negative | Does not rule out sleep apnea; an in-lab study is advised if symptoms fit | A second study may be considered if suspicion remains |
Sources: AASM (home test), AASM (sleep study), Kapur and colleagues, 2017.
The AASM diagnostic guideline calls polysomnography the standard test for adults with suspected OSA, and says either polysomnography or a technically adequate home test can be used for uncomplicated adults with signs of moderate to severe OSA. It recommends polysomnography rather than a home test for people with significant heart or lung disease, neuromuscular weakness, chronic opioid use, a history of stroke or severe insomnia (Kapur and colleagues, 2017). Lab nights are rarely perfect: many people sleep less well than at home, but this typically does not affect the results, and you usually do not need a full eight hours for a diagnosis (AASM).
What Does Your AHI Mean?
The main number from a sleep study is the apnea-hypopnea index (AHI): the average number of apneas (breathing stops) and hypopneas (breathing becomes shallow) per hour of sleep. To count, an event must last at least 10 seconds (Sleep Foundation). Doctors use AHI to classify how severe sleep apnea is in adults:
| AHI (events per hour, adults) | Category |
|---|---|
| Fewer than 5 | Normal |
| 5 to 14 | Mild sleep apnea |
| 15 to 29 | Moderate sleep apnea |
| 30 or more | Severe sleep apnea |
Source: Sleep Foundation. Children are assessed against lower thresholds, because even a few events can be abnormal in a child (Sleep Foundation).
AHI is not the whole story. Your doctor will also weigh your symptoms, oxygen levels and other health conditions when deciding on treatment, and sleep studies can show which type of sleep apnea you have as well as how serious it is (NHLBI).
How Is Sleep Apnea Treated?
Sleep apnea is a serious condition that needs treatment, and your plan may combine several options (AASM). In brief:
- Positive airway pressure (PAP). A machine blows air through a mask to hold the airway open. It is the most common treatment, and comes as CPAP, auto-adjusting APAP or bilevel BPAP (NHLBI).
- Oral appliances. Custom mouthpieces that hold the jaw or tongue forward, an option if you cannot use or do not want CPAP (NHLBI).
- Lifestyle and position. Weight loss, less alcohol, quitting smoking and sleeping on your side can all help (NHLBI).
- Surgery and implants. Including tonsil removal, jaw advancement and hypoglossal nerve stimulation, usually when other treatments have not worked (NHLBI).
- Medicine. One weight-loss medicine is approved for some adults with moderate to severe OSA and obesity (NHLBI).
Central sleep apnea is managed differently: PAP is the treatment most often used, often with bilevel or adaptive servo-ventilation devices, alongside treatment of the heart, kidney or medicine-related cause (AASM).
For a side-by-side comparison of every option, who each one suits, what the guidelines say and how to get used to CPAP, read our sleep apnea treatment options compared.
Why It Matters To Get Treated
Untreated sleep apnea can leave you short of quality sleep, which affects concentration, decisions, memory and behavior, and it raises the risk of stroke, heart attack and other serious problems (NHLBI). Drowsiness from untreated apnea also raises the risk of car crashes and work accidents (MedlinePlus). The good news is that in most cases treatment completely relieves the symptoms and problems from sleep apnea (MedlinePlus).
We cover the full list of linked conditions, from heart rhythm problems to diabetes and surgery risks, in sleep apnea health risks. For the wider picture of what poor sleep does to the body and mind, see how sleep affects your health and sleep and mental health.
Living With Sleep Apnea
- Use treatment every night. Use your PAP machine for all sleep, including naps, and take it with you when you travel (NHLBI).
- Keep follow-up appointments. Regular checkups make sure treatment is working, and you may need a repeat sleep study if you gain or lose a lot of weight (NHLBI).
- Tell your surgical team. If you need sedation or pain medicine for surgery, tell your provider you have sleep apnea so they can keep your airway safe (NHLBI).
- Do not drive drowsy. Pay attention to sleepiness and do not drive if you feel tired (NHLBI).
Sleep apnea and short sleep often overlap. If you have also been sleeping too little, our sleep deprivation guide explains the effects; if you struggle to fall or stay asleep even with apnea treatment, see the insomnia guide.
When To See A Doctor
- Someone has noticed you snore loudly, stop breathing or gasp for air during sleep (NHLBI).
- You feel very tired and sleepy during the day, or you have fallen asleep or nearly fallen asleep while driving (MedlinePlus).
- You already have treatment, but your symptoms are not improving or new ones have appeared (MedlinePlus).
Start with your regular provider; more complex cases may need a sleep doctor at an accredited sleep center (AASM).
Sleep Apnea FAQs
Can You Have Sleep Apnea Without Snoring?
It is possible. Snoring is the most common sign of obstructive apnea, but central apnea usually shows up as broken sleep, frequent awakenings and waking short of breath instead. Daytime sleepiness is a reason to ask about a test even without snoring.
Is Sleep Apnea Dangerous?
Untreated, it is linked to high blood pressure, heart disease, stroke and drowsy-driving crashes. Treatment usually relieves the symptoms.
Can A Home Test Diagnose Sleep Apnea?
Yes, for adults who are likely to have moderate to severe obstructive apnea and have no other major health problems. A negative home test does not rule it out.
What AHI Counts As Severe Sleep Apnea?
In adults, an AHI of 30 or more events per hour is classed as severe; 15 to 29 is moderate and 5 to 14 is mild.
Can Sleep Apnea Go Away On Its Own?
Not usually. Losing excess weight can improve it or sometimes resolve it, and high-altitude central apnea often settles on return to lower ground.
Can Thin People Get Sleep Apnea?
Yes. Weight is the biggest risk factor, but jaw shape, large tonsils, a large neck, age and family history matter too.