What is Obstructive Sleep Apnea?

Obstructive Sleep Apnea (OSA) is the most common type of sleep apnea and is caused by obstruction of the upper airway. It is a condition in which a person stops breathing repeatedly through the night due to obstruction and/or collapse of the upper airway causing the person to waken to breathe. This is called an apnea event. Sleep patterns are disrupted, resulting in excessive sleepiness, irritability or fatigue during the day.

An individual with OSA is usually unaware of breathing difficulties and apnea events, even upon awakening due to an apnea. It is usually identified by others witnessing the individual during an apnea event or is suspected due to effects on the body.

What causes the airway to close during sleep?

The airway at the throat is composed of walls of soft tissue which can collapse due to extra tissue in the back of the airway, such as large tonsils, a decrease in the tone of the muscles that hold the airway open, or due to the tongue falling back and closing off the airway. As we get older our muscles lose tone and when we are relaxed often after a consuming alcoholic drinks the events can be increased.

How common is OSA?

According to Snore Australia, Health Sleep Solutions and many market data reports, OSA is more common in males than in females and becomes more common with age largely affecting those over 60. In Australia OSA affects more than 1 million people of which around 9% are women and 25% are men. The prevalence of OSA is continuing to grow largely due to the ageing population and the ‘obesity epidemic’. Report show that globally it is estimated that over 100 million people suffer from a sleep disorder with over 90% of them currently untreated (America Academy of Sleep Medicine, 2014).

What degrees of severity occur with OSA?

The Apnea Hypopnea Index (AHI) is the number of apnea or hypopnea episodes recorded during the study per hour of sleep. The AHI and oxygen desaturation levels are used to indicate the severity of OSA. The results of AHI are usually expressed as the number of events per hour and based on the AHI are classified as follows:

  • None/Minimal: AHI < 5 per hour
  • Mild: AHI ≥ 5, but < 15 per hour
  • Moderate: AHI ≥ 15, but < 30 per hour
  • Severe: AHI ≥ 30 per hour

This means that a person suffering from severe OSA with as many 50-60 events can be woken from sleep up to every minute during the night.

What are the symptoms of OSA?

The main night time symptoms of OSA are:

  • Loud snoring
  • Cessation in breathing accompanied with gasping episodes when sleeping
  • Restless sleep

The main day time symptoms of OSA are:

  • Morning headaches
  • Waking up tired
  • Irritability