Apnoea (or 'apnea' depending on which part of the world you come from) is derived from the Greek: a- without, and pnoea- breathing.
In the context of sleep disorders, apnoea is a condition where the sufferer repeatedly stops breathing while asleep. A person suffering from 'mild' sleep apnoea will stop breathing between 5 and 15 times per hour while asleep. A 'moderate' apnoea sufferer will stop breathing between 15 and 30 times per hour; and a 'severe' apnoea sufferer will stop breathing 30+ times per hour.
To be considered an apnoeic 'event', each apnoea experience must last for at least 10 seconds -- although in many of the sleep studies we've done for patients, we've seen apnoea events lasting up to 2 minutes. More typically, apnoea events last for around 20 to 40 seconds at a time.
Even a mild apnoea sufferer will therefore stop breathing somewhere between (at least) 50 seconds per hour (being 5 events at just 10 seconds each) through to as much as 10 minutes per hour (being 15 events at 40 seconds each). Obviously, in moderate and severe cases of apnoea, the breathing stoppages are for much greater periods of time. We have regularly seen patients who are not breathing for more than half the time they are asleep.
The negative impacts of apnoea are many and uniformly negative.
At the milder end of the scale, the patient suffers from waking tiredness, daytime sleepiness, fatigue, lethargy and loss of cognitive ability. In more severe cases, apnoea is clearly linked to acid reflux, hyptertension, metabolic retardation and consequent weight gain/obesity, ischemic heart disease and stroke.
Apnoea is a 'silent killer' because it happens when people are asleep -- and the apnoea event is often characterised by the cessation of snoring. The noise of snoring might be irritating to the snorer's partner, but the silence periods between snoring could be deadly.
If you snore, or know someone who does, arrange a sleep study immediately. For more information, visit our Sleep Studies page.