Why don't we cough in our sleep?

I know it’s possible - I’ve woken up to cough before, although not many times. But I’ve noticed that I can have a cough in the day and sleep through an undisturbed night, and then have a cough the first thing when I wake up. So what’s stopping me from coughing during the night, and why can’t I use that facility during the day?

You can cough during the night. You can also sneeze, walk, talk, poop, pee, etc…

But you usually don’t because the body has a natural way of preventing these things by "paralyzing’ (for lack of a better term) certain neurotransmitters during sleep. If it didn’t we’d be waking up for every little itch and wouldn’t get any rest.
Doing any of these during sleep is more of an anomaly than the norm thanks to how the brain works during sleep.

Hmm. Well, okay. Let me rephrase the question. Why doesn’t the brain (or cough medicine) paralyse the relevant neurotransmitters while awake? I mean, if you don’t HAVE to cough, why do you cough?

Because you wouldn’t be able to move.

You are sleeping and only know you are coughing when it is bad enough to wake you up. The coughs you don’t have in your sleep are the habit cough, the tic cough, and the conscious of wanting to clear your throat before you talk cough. The cough of a cold, of asthma, or allergies … those are all there in your sleep. Often worse then even.

Its actually part of the assessment I use for kids with chronic cough … do they cough in their sleep? (Parents know, the kids don’t, obviously.) A cough that is gone as soon as they fall asleep is behavioral, such as tic related. The chronic coughs that are worse in the middle of the night are more likely from asthma, sinusitus, allergies, or somesuch.

The “why” do some get tics and habit coughs is a different conversation.

The short answer is faulty premise.

This hints at an answer to a question I posted some years ago here (without any satisfying responses, by the way), about sneezing. Sneezing, being essentially a reflex, and therefore out of the brain’s control to begin with, seems to stop at night. I didn’t see why this should be so. I will take pkbites’s response as a good beginning, but I’d like to know what “better term” there is for the assertion that certain neurotransmitters are “paralyzed” during sleep. Neurotransmitters in the spinal cord where the reflex arc occurs? How? The phrase sounds like pseudoscience and requires elucidation and elaboration. What is the actual neuroanatomy behind this claim?

Madame P. says I cough in my sleep every night. I have COPD, and am taking meds for it.

Unfortunately there isn’t that much better of a term. The paralysis occurs during Rapid Eye Movement (REM) sleep (the portion of sleep you dream in), not during non-REM parts of the sleep cycle, and is called, creatively enough, REM sleep paralysis.

The neuroanatomy is that it begins in the brainstem (the ventromedial medulla and the dorsolateral pons), and spreads through the medulla and spinal cord, decreasing the activity of the motoneurons in the brainstem and spinal cord, causing the flaccid paralysis associated with REM sleep.

There is more than one neurotransmitter system involved and neither alone is sufficient to cause REM sleep paralysis. I think that article will provide you with sufficient elucidation and elaboration.

Again, there is no paralysis during most of sleep, and coughing and sneezing does occur during sleep, albeit significantly suppressed during REM (which is about 20 to 25% of normal adult sleep).

Ok, don’t laugh, but I had an older cat with a chronic cough, and he always coughed when he was asleep! That was the first I realized that sleepers do a lot of stuff while they’re asleep that they’re just not aware of, or they forget almost instantly.

Coughing and sneezing is nothing - wait til you live with someone who makes nighttime sleeping fridge raids. “Honey, why is the half-gallon of milk I bought last night already gone…?”

Hopefully this is related enough to the OP and not a complete tangent, but is there a similar mechanism at work for loud or aggressive snoring to not be heard/remembered – and in far more cases than not – it never seems to wake the snorer up (though if someone else is doing the snoring while both asleep, it’ll wake the non-snorer up)?

Well snoring tends to be worst during the deepest non-REM phases of sleep (“slow wave” aka stages 3 and 4) and REM … not the lighter phases of sleep that people are more easily aroused from.

Thanks for all the interesting replies. I’m still a little baffled that, for the past few days, I’ve had a cough associated with a cold that has disappeared at night (my wife is a light sleeper and would have known if I’d coughed while asleep). As my brain wouldn’t allow a harmful process to occur during sleep, presumably the absence of the cough reflex is not in itself harmful; I can breathe perfectly normally (no snoring, either, by the way) without coughing. Yet when I wake up, after the usual period of slobbering idiocy, I find myself coughing again. Unnecessarily, irritatingly … why can’t the cough inhibitors that kicked in during the night continue their useful and appreciated work during the day? Are they tired?

The human anatomy makes protection of our airway problematic, since the machinery for swallowing runs adjacent to the machinery for breathing.

It is really protection of the airway that is waking you up when you cough. Non-productive coughs may not “wake up” any given individual in the same sense that itching may or may not keep you awake. I put “wake up” in quotes because the state of consciousness during sleep is a complicated thing that has a fairly large range from what we might call light dozing to a state of fairly profound unarousability. And of course the activity of the brain continues for poorly understood reasons that separate off an awake state from an asleep one.

If the reason you are coughing is to protect your airway from accumulating fluids such as pulmonary tree mucus or refluxed gastric contents, the chances are much higher the coughing will wake you up so the body can make sure the fluid stays out of the trachea.

Protection of the airway is a very deep reflex that sends a very loud alarm signal to become alert and prevent anything foreign from obstructing the airway. When we give chemicals for sedation and anesthesia, it’s one of the last mechanisms to go to “sleep.”

As with everything about physiology, there are nuances, such as those poor souls who chronically aspirate, or who are wired such that they don’t protect their airway well. But in general, it’s the airway issue and not necessarily the cough per se that is keeping you awake.

*“But in general, it’s the airway issue and not necessarily the cough per se that is keeping you awake.”
*
But it’s not keeping me awake, because I don’t cough in my sleep. Nor do I sneeze - another involuntary reflex that sleeps when I do. This makes me think that if I don’t have to cough/sneeze to keep breathing/stay alive, my body/brain is dealing with the problem in a smarter way than it does when I’m awake.

:rolleyes:

You also do not recall farting in your sleep. Surely you wife would wake up if you did. There must be some mechanism that prevents you from farting while asleep!

Get yourself this app. You may be surprised.

I know for a fact that I do cough some in my sleep, ditto sneezing, but I wonder if some of the reduction is that we’re not breathing as deeply, hence less volume of air to irritate things.

As an aside, neither sneezing nor coughing works well when you’re using a CPAP :p.

Oh, yeah, we totally cough in our sleep. We just aren’t aware of it.

When I was 13 or 14, I came down with some lower respiratory infection. The coughing wasn’t so bad during the day, but that night I was coughing so hard, I woke my parents up. They woke me up when they came to check on me. No idea I’d been coughing.

Mom made me take cough syrup, which I hated, so that she could get back to sleep.