What is Obstructive Sleep Apnea?


Obstructive Sleep Apnea is a serious medical disorder in which your throat tissues collapse during sleep. This collapsed tissue obstructs air from reaching your lungs when you breathe in; you must actually “awaken” (often unconsciously) to breathe. The breathing pauses, called “apneas”, can last for 10 to 30 seconds, maybe longer. People with sleep apnea can stop breathing dozens or even hundreds of times each night.

How Common is Obstructive Sleep Apnea (OSA)?

Obstructive Sleep Apnea affects about 1 in 5 Canadian adults¹ which is about as common as diabetes, and Sleep Apnea is quite significantly under-diagnosed.

Of the 20% of Canadians with Obstructive Sleep Apnea, about 6.5% have moderate to severe OSA. The remaining people have mild to moderate Obstructive Sleep Apnea.

What Causes Obstructive Sleep Apnea?


Normal Airway

While you are awake, the muscles in and around your throat and the back of your tongue are kept active by signals from the brain. When you breathe in, the air easily flows through the throat to your lungs


During sleep, these signals from the brain are reduced. This causes the muscle tone in your throat’s soft tissues to relax. The throat walls can begin to narrow (SNORING) and as the muscle tone is further relaxed, your throat walls may collapse and breathing can be obstructed or blocked (AIRWAY BLOCKED). As a result, your breath does not reach your lungs and your blood’s oxygen levels begin to drop.

Airway Blocked

When your brain realizes that you are short of oxygen it will often wake you up enough to snort, take a few deep breaths, and then you will go back to sleep. You are not in a conscious state but are technically awake. Once you are back asleep this cycle starts over again.

Most people do not remember these mini awakenings; however they have a major negative impact on the quality of your sleep leaving you exhausted the following day.

Signs and Symptoms of Obstructive Sleep Apnea (OSA):

It can be difficult to identify sleep apnea, since the most prominent symptoms occur only while you are sleeping. Secondly, most people “think” they sleep fine since they often do not remember the “mini awakenings”. It is important to ask a bed partner about your sleep habits or if you are alone, portable monitors can provide recordings of important parameters (oxygen levels and breathing) during sleep.

The following signs and symptoms are common and are often used as part of an Obstructive Sleep Apnea evaluation:

  • Fatigue or daytime sleepiness
  • Breathing pauses during sleep
  • Loud snoring
  • Depression, memory lapses
  • High blood pressure
  • Sexual dysfunction
  • Frequent morning headaches
  • Sudden awakenings with a sensation of gasping or choking

Tips on Getting a Good Night’s Sleep

See our Sleep Hygiene Brochure

1 Young, T., Peppard, P.E., & Gottlieb, D.J. (2002). Epidemiology of obstructive sleep apnea: a population health perspective. Am. J. Respir. Crit. Care Med, 165, 1217-1239.