What is Sleep Apnoea?

Learn more about sleep apnoea:

Snoring and sleep apnoea are common sleep-disordered breathing (SDB) problems that can affect your sleep, health and quality of life.

Read on to find out more about:



What Causes Sleep Apnoea?

Sleep Apnoea (meaning absence of breath), is caused by the closing of the soft tissue in the upper airway. It occurs when breathing stops during sleep for at least 10 seconds at least five times an hour.

This can either be weight related, physiological (i.e. simply a narrow airway or pronounced under-bite) or a physical obstruction (i.e. tonsils).
Mild sleep apnoea causes few symptoms, but the condition may lead to low oxygen levels, which can lower life expectancy by up to 15 years.


Common Symptoms of Sleep Apnoea

  • Excessive daytime sleepiness, fatigue or lethargy
  • Gasping, snorting or choking during sleep
  • Poor concentration
  • Poor memory
  • Loud snoring
  • Falling asleep or needing a daytime nap
  • Irritability, depression, anxiety, mood or behaviour changes
  • Insomnia, disturbed or restless sleep
  • Morning headaches
  • Change in personality
  • Increased frequency of urination at night
  • Rapid weight gain or difficulty losing weight

Types of Sleep Apnoea

There are three types of sleep apnoea: obstructive, central, and mixed:

Obstructive Sleep Apnoea (OSA)

The most common type of sleep apnoea. It occurs when your upper airway closes but your efforts to breathe continue. The primary causes of upper airway obstruction are lack of muscle tone during sleep, excess tissue in the upper airway, and anatomical abnormalities in the upper airway and jaw.

Central Sleep Apnoea (CSA)

This affects only 5-10% of the sleep apnoea population. It occurs when your breathing stops but your airway is open. This cessation of breathing results from the body's failure to breathe automatically. It's as if a short circuit prevented the brain from keeping the respiratory system functioning properly.

Mixed Apnoea

A mixture of both OSA and CSA.


Snoring and Sleep Apnoea

Snoring and sleep apnoea often occur together, caused by changes in your upper airway while you sleep. Your airway may narrow, limiting airflow as you breathe; it may vibrate, commonly heard as snoring; or it may collapse, so you stop breathing.

Your airway may even move through all three stages (see images):


Healthy airway


Partially obstructed airway


Obstructed airway

When tissues obstruct the upper airway completely, they prevent breathing. They actually work to suffocate the sleeper. The sleeper wakes up enough to regain control of the upper airway, breathe again, and then fall back to sleep. This happens from dozens to hundreds of times per night for people with OSA, but they usually don't remember waking up.

Effects of Sleep Apnoea

Each obstruction deprives the body of oxygen and forces it to retain carbon dioxide that it would normally exhale. As a result, the body's blood gases get out of balance, and the body is subjected to a 'toxic' environment. When the body sets off 'alarms' that it needs more oxygen, the brain wakes the sleeper, breathing resumes, and the individual falls back to sleep until the next obstruction occurs.

These obstructions increase heart rate, raise blood pressure, and eventually blunt the body's automatic response system, resulting in increasingly more severe apnoeas and hypopnoeas.
The brief wake-ups that people with OSA experience also diminish their quality of sleep, resulting in sleep deprivation.