Sleep apnoea occurs when a person regularly stops breathing for 10 seconds or longer during sleep. It can be mild, moderate, or severe, based on the number of times an hour that they stop breathing (apnoea) or that airflow to your lungs is reduced (hypopnea). This is called the apnoea-hypopnea index (AHI).
Obstructive sleep apnoea is the most common type of sleep apnoea. It occurs when the soft tissue in the back of your throat relaxes during sleep and blocks the airway, often causing you to snore loudly.
Central sleep apnoea is a much less common type of sleep apnoea that involves the central nervous system, occurring when the brain fails to signal the muscles that control breathing. People with central sleep apnoea seldom snore.
Complex sleep apnoea is a combination of obstructive sleep apnoea and central sleep apnoea.
Key stages include:
1. Mild apnoea
Mild apnoea is defined as 5 to 14 episodes of apnoea or reduced airflow to the lungs every hour. Symptoms may include drowsiness or falling asleep during activities that do not require much attention, such as watching television or reading. These symptoms may cause only minor problems at work or while spending time with friends or family.
2. Moderate apnoea
Moderate apnoea is defined as 15 to 29 episodes of apnoea or reduced airflow to the lungs every hour. Symptoms may include drowsiness or falling asleep during activities that require some attention, such as attending a concert or a meeting. These symptoms may cause moderate problems with work or social functioning.
3. Severe apnoea
Severe apnoea is defined as 30 or more episodes of apnoea or reduced airflow to the lungs every hour. Symptoms may include drowsiness or falling asleep during activities that require active attention, such as eating, talking, driving, or walking. These symptoms may cause severe problems with work or social functioning.
If you think you may have a sleep-disorder or would like to change your sleep-disorder treatment, seek medical advice from a sleep physician.