What is sleep apnoea?
Sleep apnoea is a sleep disorder that’s characterised by cessation or interruptions of breathing during sleep, resulting in oxygen deprivation and fragmentation of sleep.
There are three types of sleep apnoea:
- Obstructive sleep apnoea (OSA). This is the most common type of apnoea. It occurs due to an obstruction or weakness in the airway that results in the obstruction of airflow to the lungs during sleep. Each obstruction needs to last a minimum of 10 seconds for it to be classified as abnormal. The collapse or narrowing of the upper airway may be a result of several factors, including inherent physical characteristics, excess weight, and alcohol consumption before going to bed.
- Central sleep apnoea. This is caused by a delay in the signal transmitted from the brain to elicit breathing, and is usually part of a brain or cardiac disorder (these disorders often follow after a stroke or cardiac failure).
- Mixed sleep apnoea. As the name suggests, this type of apnoea is more or less a mixture of the above. It occurs less frequently than obstructive sleep apnoea, but more frequently than central sleep apnoea.
Who gets sleep apnoea?
The prevalence of obstructive sleep apnoea (OSA), the most common type of apnoea, has been estimated to be between 3% and 7% of the male adult population.
There are multiple risk factors, which include:
- Male sex
- Middle age
- Increased neck circumference
- Elevated body mass index (BMI)
The male-to-female ratio is approximately 4:1. After menopause, the male-to-female ratio becomes almost equal.
Reviewed by Dr Irshaad Ebrahim, specialist neuropsychiatrist in sleep disorders at The London Sleep Centre and The Constantia Sleep Centre. FRCPsych. April 2018.