Why does snoring exist?

Why hasn't an advertisement for a sleeping creature been selected against in evolution?
16 January 2018



Why does snoring exist? Shouldn’t it have been selected against? I know my dog snores like anything, but does it exist in wild animals?


Chris Smith asked sleepologist Nick Oscroft for his opinion on this snooze-fest...

Nick - That’s a fantastic question! One of the things that struck me about snoring is evolution. You said that why hasn’t it been evolved out? Well, the shape of our faces has changed quite considerably since we’ve transitioned from being apes into hominids, and then to humans. That’s aided speech, we’ve changed our diets, so I think all these changes may have predisposed us, to a degree, to snoring.

What is snoring? It’s turbulent airflow through your upper airway. Lots of things can make that worse: obesity is a big problem. We know that weight gain tends to make snoring worse.

Chris - Why?

Nick - Why? Because you lay down fat, as well as peripherally, internally around the larynx and the upper airway, and that narrows the upper airway. Also, most of us when we go to sleep the muscles in our pharynx relax so the upper airway, the muscles relax. If you fat-load that, it will shrink in volume and, therefore, you’ll get more turbulent flow through your upper airway. Also, it can predispose you to medical problems like sleep apnea where actually the throat shuts down during sleep because the muscles become too relaxed and that caused lower quality sleep and daytime sleepiness. Alcohol and various other things that people do make snoring a lot worse.

In terms of why hasn’t it been weeded out in evolution? I was interested by that. One theory I thought about was if you snored do you keep people around you awake? Does that actually protect you in evolutionary terms? It’s a controversial thought!

Chris - So you’re saying it’s been selected in? If your husband’s snoring and you’re therefore kept awake all night then you can wake him up if any danger appears. That’s a brilliant suggestion.

Nick - It might be a selection pressure - I don’t know.


Dan - I was interested on that because I think part of the question was to do with animals and my dogs both snore. They’re terrible at it. But I was just wondering, now you’ve brought that up about this selection it’s made me almost rethink because in the animal kingdom you would almost have thought it was counterintuitive the fact that you’ve got an animal that’s snoring. But I’m just wondering if it’s the pack animals that snore, and if we take the solitary animals. If the solitary animals don’t snore because I like that idea that there’s somebody in the pack that’s more alert.

Nick - Well, I’ve been to zoos and I’ve seen many animals snore. With dogs I don’t know if, because they've been bred over time for certain characteristics, and we know certain bad characteristics have been bred into dogs in terms of the shape of their snouts, so we might be responsible, in part, for making dogs snore by the way we’ve selected them.

Chris - What about doing something about it? You’ve mentioned some of the points so you could reduce your alcohol consumption. Weight loss: presumably if you move some of the fat from around the internal tissues. I didn’t realise we accumulated fat in the way you’re saying inside and narrowed the airway but that should help to. But is there anything else, if someone’s a really bad snorer, that they could do about it?

Nick - Weight loss is normally top of the list. Also, avoiding supine sleep, so avoiding lying on your back whilst you are asleep, that almost tend to make…

Chris - You don’t have a lot of choice if you’re asleep though. You don’t really dictate what position you’re in can you?

Nick - You can do. There’s various strategies you can adopt.

Chris - The whole stitching cotton reels and fir cones into the back of your pyjamas - that idea? Is that what you’re getting at?

Nick - Certain people do do that. One of my more ingenious female patients puts her bra on backwards and puts…

Chris - Tennis balls in there or something?

Nick - Well, it’s a rubber dog ball. It’s quite spiky and that keeps her of her back so that’s quite inventive when she told me about that. I’ve suggest that to a few gentlemen, but they’ve blanched at that thought.

Chris - I’m not surprised!

Nick - Some people use foam wedges or pillows to stop themselves rolling over to their back. Partners are often helpful…

Chris - An elbow?

Nick - Indeed! There are biofeedback devices you can can buy that vibrate when you start snoring loudly and get you to roll off or change position to help with that. If you want to try something a bit more invasive there are devices called Mandibular Advancement Devices. They’re devices that go in the mouth, fit the teeth top and bottom and pull the bottom jaw forward. So they are a way of reducing snoring volume and also we use them to treat mild to moderate sleep apnea. But sometimes it’s just a fact of life.

Chris - I should just start with the simple stuff and build up from there then?

Nick - Indeed.


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