NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Informed Health Online [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-.

Cover of Informed Health Online

Informed Health Online [Internet].

Show details

Obstructive sleep apnea: Overview

Created: ; Last Update: July 30, 2015; Next update: 2018.


We all know what it is like to feel tired after a sleepless night because of things like noise, worries or stress. But what if you do actually get enough sleep and still feel absolutely beat the next morning? This is normal for many people with obstructive sleep apnea (OSA): They do not get enough air while they are sleeping (but do not usually notice this), have breathing pauses, and feel very sleepy during the day. In the long term, this increases their risk of developing other illnesses and can have a huge effect on their quality of life.


People who have obstructive sleep apnea usually snore very loudly and regularly have phases of shallow breathing (hypopnea) and breathing pauses (apnea) that last longer than ten seconds while they are sleeping. Snoring itself is harmless; it is only classified as sleep apnea if you have breathing pauses too.

The following symptoms may also be signs of sleep apnea:

  • Night sweats and frequent urination
  • Waking up suddenly, sometimes with a racing heartbeat and shortness of breath
  • Dry mouth when waking up
  • Headaches in the morning
  • Exhaustion during the day
  • Poor concentration

Causes and risk factors

Sleep apnea is caused by the muscles of the upper respiratory system relaxing. Your throat then becomes narrow or even completely blocked, which leads to loud snoring noises when you breathe in and out.

As a result, your body does not get enough oxygen. Your pulse and blood pressure fall too. The part of your brain responsible for breathing sets off an alarm and triggers a wake-up call, causing you to wake up briefly, usually without realizing it. This interrupts your natural sleep pattern, your heart starts beating faster and your blood pressure rises. If this keeps happening throughout the night, it may prevent you from entering deep sleep, which is what is needed to get restful sleep.

Illustration: Normal breathing

Illustration: Obstructive sleep apnea

Being very overweight and having unusual features in the mouth and throat area are common causes. These unusual features include enlarged tonsils, a small lower jaw, the position of the tongue and a small soft palate. Nasal breathing is sometimes obstructed too. Sleeping on your back can make snoring and breathing difficulties more likely, but is rarely the sole cause.

Drinking too much alcohol and taking sleeping pills or sedatives relaxes the throat muscles and can make sleep apnea worse. The likelihood of developing obstructive sleep apnea increases constantly after the age of 45.


It is estimated that 4 out of every 100 middle-aged men and 2 out of every 100 middle-aged women have obstructive sleep apnea that causes symptoms.


Severe sleep apnea makes you feel constantly worn out and tired. Not getting enough restful sleep can have longer-term effects on your mood too. If you generally do not feel as well as people who usually get a good night's sleep, you are also more likely to become depressed.

High blood pressure (hypertension) and other cardiovascular diseases are more common in people who have sleep apnea. They are more likely to have a heart attack, a stroke or heart rhythm problems (arrhythmias) as a result.

Breathing pauses do not always pose a problem or health risk. If they only occur now and then, are short, and do not cause tiredness during the day, there is usually no reason to worry. Yet it may be a good idea to keep an eye on any breathing difficulties and see a doctor if they cause more long-term problems.


If it is thought you might have obstructive sleep apnea, your doctor will first ask you about your symptoms and lifestyle habits. This is usually followed by a general physical examination. You may be given a portable monitoring device which can be used when you are asleep to record things like your breathing, heart rate, blood oxygen levels, snoring, and body position. If there are any irregularities, further tests in a sleep laboratory may be a good idea.

Sleep laboratories have bedrooms that can be used for one or more nights. Here your sleep is monitored using different recording devices and a video camera. As well as recording your breathing, pulse, blood pressure and blood oxygen levels, they also record your brainwaves, and your eye and leg movements during sleep. Using the recorded data, the different sleep phases can be analyzed to see how long and how well you slept, and whether you spent enough time in deep sleep and dreaming. In people with sleep apnea, the machines can record how often breathing pauses occur, how long they last, during which sleep phases they occur, and the patient's sleeping position at the time. It is also possible to tell how they affect the cardiovascular system and blood oxygen levels.


If you are very overweight, losing weight can help improve sleep apnea. There are also many treatment options that aim to relieve sleep apnea. These include machines that support breathing during the night, surgery, and special aids such as mouth guards. Some of these treatments have been scientifically proven to help people with sleep apnea. Medication is currently not used for the treatment of sleep apnea. There is no scientific evidence that the available medications work.

The most effective treatment for severe sleep apnea is called CPAP therapy. CPAP stands for “continuous positive airway pressure.” In this treatment approach, air is taken from the immediate surroundings and blown into your airways at night using low pressure. While you sleep, you wear a breathing mask that is connected to a machine called a respirator. The pressure keeps the upper airways open. People who use this machine have fewer breathing pauses, or even none at all. This can noticeably improve the symptoms such as tiredness during the day. Common side effects include a dry throat and an irritated, sometimes blocked nose.

Everyday life

Obstructive sleep apnea can greatly affect quality of life. Sleeping poorly can make you feel tired and “beat” during the day. Some people involuntarily fall asleep for a very short time during the day too – a phenomenon known as “microsleep.” This mostly happens when sitting or during quiet and more passive situations, for example at a concert, or while reading or watching television. It can become dangerous if this happens when you are driving. Getting too little sleep can also cause problems with concentration or memory.

Sleep apnea can affect your relationship if loud snoring disturbs your partner’s sleep, making them feel tired and irritable during the day too. The breathing pauses might also cause your partner to worry about you.

CPAP therapy is the most effective way to relieve obstructive sleep apnea, but it is difficult to get used to. Not everyone wants to wear a breathing mask every night. Patient education programs can help you get to grips with CPAP therapy. Joining a self-help group and talking with other people who have sleep apnea can help too. There are now self-help groups for people with sleep apnea in many cities in Germany. The most important thing is to be patient and get the support you need if you have any problems. If you manage to make breathing therapy a part of your daily routine, it can really improve your quality of life.

Further information

You can find more information on regional support services in Germany by contacting the Independent Patient Counselling Service Germany (in German: Unabhängige Patientenberatung – UPD).


  • Araghi MH, Chen YF, Jagielski A, Choudhury S et al. Effectiveness of lifestyle interventions on obstructive sleep apnea (OSA): systematic review and meta-analysis. Sleep 2013; 36(10): 1553-1562. [PMC free article: PMC3773205] [PubMed: 24082315]
  • Balk EM, Moorthy D, Obadan NO, et al. AHRQ Comparative Effectiveness Reviews.  Diagnosis and Treatment of Obstructive Sleep Apnea in Adults. Rockville (MD): Agency for Healthcare Research and Quality (US); 2011.
  • Broström A, Johansson P, Strömberg A, Albers J et al. Obstructive sleep apnoea syndrome – patients´ perceptions of their sleep and its effects on their life situation. J Adv Nurs 2007; 57(3): 318-327. [PubMed: 17233651]
  • Chai CL, Pathinathan A, Smith B. Continuous positive airway pressure delivery interfaces for obstructive sleep apnoea. Cochrane Database Syst Rev 2006; (4): CD005308. [PubMed: 17054251]
  • Giles TL, Lasserson TJ, Smith BH, White J et al. Continuous positive airways pressure for obstructive sleep apnoea in adults. Cochrane Database Syst Rev 2006; (3): CD001106. [PubMed: 16855960]
  • Greenstone M, Hack M. Obstructive sleep apnoea. BMJ 2014; 348:g3745. [PubMed: 24939874]
  • Hensley M, Ray C. Sleep apnoea. BMJ Clin Evid 2009.
  • Mason M, Welsh EJ, Smith I. Drug therapy for obstructive sleep apnoea in adults. Cochrane Database Syst Rev 2013; (5): CD003002. [PubMed: 23728641]
  • IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

    Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. We do not offer individual consultations.

    Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

© IQWiG (Institute for Quality and Efficiency in Health Care)
Bookshelf ID: NBK279274


Informed Health Links

Related information

  • PMC
    PubMed Central citations
  • PubMed
    Links to PubMed

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...