What does it actually mean if I snore?
By Adrian Williams
There is an old adage ‘laugh and the world laughs with you, snore and you sleep alone’ which underscores the significance of snoring for many people. And by ‘many people’, I mean a half of men in middle-age and perhaps a quarter or more of women will have somewhat problematic or intrusive snoring.
So why does this happen? The noise is generated of course in the area of the throat where the tissues, including the palate and the walls of the throat or pharynx vibrate, which happens if the breathing passage is narrow enough to cause the flow of air to be turbulent.
What this means is that we are predisposed to snoring if the pharynx is sufficiently narrow. This is an inherited aspect of our anatomy which cannot be naturally modified because we have adopted an upright posture in evolution instead of walking on all fours. This has led to a right angle bend in the throat instead of a straight passage which keeps the throat open. Snoring is, in fact, one of the most heritable things identified in twin populations, underscoring this anatomical contribution.
We can imagine therefore that if the pharynx is narrow enough to allow a person to snore in sleep, it might reach the point of closing off or almost closing off, a condition that we call sleep apnoea. When awake, the muscles that hold the airway open are themselves ‘awake’, and therefore much more active.
And here is the crux; sleep apnoea is also very common, with half of snorers having some interrupted breathing when they are asleep, translating into possibly 25% of men and 15% women in middle age. The number of interrupted breaths may of course be quite small, developing first during the time we are in dreaming (REM sleep) which occurs in cycles each 90 minutes during the night and amounting to 20% of total sleep time. In REM sleep the body is physically paralysed to prevent us acting out our dreams, and that paralysis includes the muscles in the throat so that the pharynx (throat) becomes more relaxed and floppy. The number of absent breaths may increase with time and with body position, particularly sleeping on one’s back when the jaw and tongue tend to fall back causing the breathing passage to become further restricted, then disturbing sleep leading to other problems and the need for treatment. More in another blog!
However, there are other influences causing snoring too. One is the ease or difficulty breathing through the nose. If you were to narrow the nares with your fingers and breathe through your nose you will feel a negative pressure in the ears which works in the area of the pharynx as well to further narrow that already narrow tube. Another factor is the presence of adipose tissue or fat. Strangely, small pads of fat sit alongside the pharynx and these expand with increased body weight to the extent that even a millimetre of extra fat in these pads will narrow the tubes sufficiently to cause more sleep apnoea.
This cross section of the throat area shows the airway and the (expandable) fat pads alongside.
The importance of snoring, then, is the indication that there may be some sleep apnoea which is a condition that might disturb sleep quality with a number of consequences that are considered very relevant, and include high blood pressure, cardiovascular disease including stroke, and diabetes, which we can discuss another time
But does snoring without any sleep apnoea, cause a problem? The stock answer is that there is no evidence for this but the vibration might harm the area of the pharynx (a possibility which has been discussed in the sleep world); and also of course the noise itself could perhaps be disturbing bed partners, something that has in the past been called ‘spousal arousal’ (of the wrong sort!)
More of ‘What does it actually mean’ soon