Eli5 – how can people not snore laying down while awake but then snore as soon as they fall asleep

Question

I know head position and all that affects snoring but how can someone be awake and laying down and not snore, but then fall asleep in the same position and then start snoring

In: 79

Answer 1

From a doctor:

When you are awake, your mouth, tongue and throat muscles that make up your airway are constantly adjusting and tensing a little here and there – this is called muscle tone. We don’t notice it as it’s mostly not under our conscious control (just like we don’t have to think about standing to stay standing, thankfully). When you tense up a muscle it gets firmer. This is one of the reasons why our breathing pipe doesn’t collapse in on itself, as it is supported in part by those muscles staying firm, and our tongue stays in the front of our mouth because we like it to be there.

When we are asleep however, our muscles relax a bit. Our tongue might fall into the back of our throat and the rest of the other squishy bits in our noses, mouths and back of the throat can get too floppy. We also relax our neck muscles and our head can tilt forward, which kinks our airway.

So now instead of a smooth path for the air to flow into the lungs, there’s squishy muscles and other tissue in the way. We take a breath, those bits vibrate and create that irritating snoring noise. “Heavy breathing” is just a mild version of snoring.

Now the bonus ELI5 you didn’t ask for…

The more relaxed, or unconscious you are, the more likely you are to snore… or even block off your airway completely. People waking up from an anaesthetic, or people who are super-drunk often snore. If you perform a chin lift or jaw thrust (if you are trained, like in lifesaving courses) you straighten out and unblock their floppy (collapsed) airway and the snoring often stops instantly, which is sooooo satisfying 🤣

People with obstructive sleep apnoea have such floppy airways they completely block off and stop breathing (“apnoea”). When their oxygen levels drop sufficiently their brain wakes them up just enough for them to regain muscle tone, open up their airways, take a gasp and get some air in. This is one of the reasons why people with OSA are so tired as they are constantly waking up a tiny bit all night.