Obstructive sleep apnoea (OSA) occurs when the walls of the throat relax and narrow or close during sleep, interrupting normal breathing. This disturbs sleep.
When asleep, OSA may cause snoring and snorting alongside interrupted breathing. When awake, OSA causes excessive daytime sleepiness (hypersomnia). Hypersomnia poses a danger to driving and should be reported by patients and explored by doctors - the driving licencing/regulatory agency (such as the DVLA) should be informed.