What is sleep apnoea, and why does it matter?
Repeated interruption of breathing during sleep, lasting seconds at a time and occurring anywhere from a few to hundreds of times a night — and it matters because the person affected is usually unaware of it entirely, while the consequences accumulate for years.
What happens mechanically. In obstructive sleep apnoea — by far the most common form — the muscles of the throat relax during sleep and the airway collapses, blocking airflow. Oxygen falls, carbon dioxide rises, and the brain triggers a brief arousal to restore muscle tone and reopen the airway. The sleeper does not wake fully and does not remember it, but sleep is fragmented hundreds of times.
Central sleep apnoea is different and rarer: the brain fails to send the signal to breathe, rather than the airway blocking.
Why it is so often missed. The symptoms are attributed to other things: tiredness to being busy, snoring to being a snorer, morning headache to sleep position, irritability to stress. The diagnosis is frequently made because a partner describes the breathing stopping, which is the single most useful piece of information available.
The symptoms worth recognising: loud snoring with pauses; gasping or choking arousals; unrefreshing sleep however long it lasts; excessive daytime sleepiness, including falling asleep watching television or — dangerously — driving; morning headache; dry mouth; nocturia; poor concentration and memory; and low mood.
Why it matters medically. Untreated, it is associated with hypertension that resists treatment, cardiovascular disease, stroke, arrhythmias, type 2 diabetes, and substantially increased road traffic accident risk — which carries a legal obligation to notify the licensing authority where sleepiness affects driving.
Who is at higher risk: raised body weight and neck circumference, male sex, increasing age, large tonsils, a receding jaw, nasal obstruction, alcohol and sedatives, and menopause.
How it is diagnosed: a sleep study, frequently a home device measuring airflow, oxygen and effort.
What treats it: CPAP, which is highly effective when used; mandibular advancement devices for mild to moderate cases; weight loss; positional therapy; and surgery in selected cases.
General information, not medical advice.