Visual guide
What changes when the airway narrows
In obstructive sleep apnoea, relaxed tissue can reduce the space available for air to move through the upper airway.
What happens to the airway
During sleep, muscles supporting the tongue, throat and soft tissues naturally relax. In obstructive sleep apnoea, the available space becomes too narrow for normal airflow. Breathing may reduce or stop briefly until the brain triggers a short arousal that restores the airway.
These repeated events can fragment sleep even when the person does not remember waking.
Body and airway factors
Features that can reduce airway space or make it more likely to collapse include:
- A larger neck or more tissue around the upper airway.
- The shape or position of the jaw, tongue, palate or other airway structures.
- Large tonsils or adenoids, particularly in children.
- Nasal congestion or obstruction that makes breathing during sleep more difficult.
Health and lifestyle factors
Factors associated with a greater likelihood of obstructive sleep apnoea include:
- Living with overweight or obesity, although sleep apnoea also occurs at lower body weights.
- Getting older, while recognising that children and younger adults can also be affected.
- Smoking and drinking alcohol, particularly near bedtime.
- Sleeping on the back when breathing events are position-dependent.
- Certain health conditions and medicines that affect breathing, muscle tone or sleep.
Family, sex and life stage
A family history may reflect shared anatomy or other inherited susceptibility. Obstructive sleep apnoea is diagnosed more often in men, but it can be missed in women when symptoms are attributed to insomnia, fatigue or mood changes.
Risk can also change with age and hormonal life stages. Symptoms should be assessed on their own merits rather than ruled out because someone does not fit a stereotype.
Not all sleep apnoea is obstructive
Central sleep apnoea is less common and involves the brain’s control of breathing rather than a physical upper-airway blockage. Some people have a combination of obstructive and central events. The distinction matters because assessment and treatment can differ.
What to do with this information
Focus on symptoms and their effect on daily life, not just your number of risk factors. If breathing pauses, gasping or choking have been witnessed, or daytime sleepiness is persistent, discuss this with a healthcare professional.