Obstructive Sleep Apnoea (OSA)

Obstructive Sleep Apnoea, or OSA, is a condition that affects around 4% of the Australian population. It is a condition that can affect any age group and one that often goes undiagnosed or even ignored.

obstructive sleep apnoea, sleep anatomy

OSA occurs during sleep when the airway becomes obstructed, completely blocking the flow of air and hindering breathing.As the lungs are no longer receiving air, the body’s oxygen levels fall and carbon dioxide levels increase. Receptors in the body sense this change and signals it to try and breathe as best it can, often futile due to the obstruction in the airway. The result is an abrupt arousal from deep sleep where the sleeper chokes and gasps for air.

This arousal is known as an ‘episode’. Normally only lasting a few seconds, episodes occur during the normal course of sleep with many people experiencing multiple episodes a night, even those without Sleep Apnoea. Less than 5 episodes an hour is considered normal, however those with mild OSA are diagnosed at approximately 5 or more episodes an hour, with some patients experiencing upwards of 30 (severe OSA).

These episodes are unbeknownst to the person suffering as each episode awakens them from deep sleep for a short time, yet not enough to fully wake them to a conscious level. This is a particular reason that OSA can go undiagnosed as people are simply not aware. They may wake in the morning tired or drowsy and remain so throughout the day yet not attribute this to a poor night’s sleep. While not necessarily impactful, short term issues also arise through lowered mental ability due to tiredness and OSA has been an attributing factor in accidents involving motor vehicles and workplace hazards.

Longer term problems, however, are much more serious as OSA leads to medical conditions such as hypertension (high blood pressure) and many forms of cardiovascular disease. It can also lead to decreased libido and long term decreased motor skills.

What Causes OSA?

Obstructive Sleep Apnoea is caused by the blockage of airflow during breathing. As you enter deep sleep, the muscles in the jaw, tongue and neck relax, causing a block in the airway and preventing air from entering the lungs.

causes of obstructive sleep apnoea

If you believe you suffer from OSA, you may notice that it is worse when sleeping on your back. In this position, the relaxed muscles fall directly towards the back of your neck and easily block your airway.

Sleeping on your side may actually alleviate this issue and improve sleep temporarily, however due to the nature of sleeping, unconsciously you may roll onto your back during the night.

What Are the Symptoms?

Signs of symptoms of Obstructive Sleep Apnoea are varied and easy to overlook as related to other lifestyle choices. Symptoms listed below are the most common in those who suffer from OSA:

  • Loud and continuous snoring
  • Tossing and turning during the night
  • Waking up during sleep, gasping or choking for air
  • Daytime tiredness (hypersomnia)
  • High blood pressure
  • Difficulty getting to sleep (insomnia)
  • Multiple episodes of breathing cessation

Are There Any Risk Factors?

Obstructive Sleep Apnoea can affect all ages and genders, even those who would normally be considered very healthy.

Male anatomy generally leans toward more mass in the upper torso and neck and are more likely to be diagnosed with OSA. As females approach post-menopause, the prevalence of OSA in women approaches the same range as males. Females are also often at risk of developing OSA during pregnancy.

Certain lifestyle factors such as excessive alcohol intake and smoking have been shown to cause a higher incidence of OSA.Excessive body weight or body fat levels, particularly around the neck area, can also put more pressure on the neck during sleep, causing a blockage to occur in the airway. Those with higher body weight may find it beneficial to improve their quality of sleep through relevant weight loss programs.

Obstructive Sleep Apnoea may also have a genetic relation as those with a family history are often at higher risk of developing it themselves.

What Are the Treatment Options?

OSA is a manageable, but not curable, condition. Treatment options range from wearing a mandibular splint, not unlike a mouthguard, to using a CPAP machine (continuous positive air pressure) during sleep to ensure the airway does not collapse.

Your health professional is best placed to recommend appropriate treatment depending on the severity of your sleep apnoea.


  1. http://www.ada.org.au/Australian_Dentist/July_2009/science_sleep_apnoea.aspx
  2. http://www.ncbi.nlm.nih.gov/pubmed/11991871

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