Do we sneeze when we're sleeping?

Kat Arney put Denny's question to Naked Scientist Chris Smith...

Chris - Who sneezed in their sleep? Have you ever done that?

Kat - I don't know.

Ginny - Not that I know of.

Chris - Carolin?

Carolin - I've always woken up if I sneeze while I'm sleeping.

Chris - There you go. That's the crucial answer I reckon because I have definitely done exactly that. I've woken myself up sneezing at night. I think Denny, the answer to your question is that the majority of us wouldn't know if we did sneeze in our sleep and probably, it barely rouses us. And so, as a result, we don't remember it. There's no reason why you shouldn't sneeze in your sleep. What's going on with the sneeze is that you have a circuit in your brain which detects movements or irritation of the lining in your nose. There's a lot of hairs there which if tickled or plucked, will strongly stimulate this reflex and they go back to your brain stem which connects your spinal cord to the top part of your brain where all of the centres which control breathing, coughing, blinking, the amount of saliva and eye secretions and tears you make, all of those things go on there and sneezing and hiccupping is coordinated there as well. All of these functions are preserved in your sleep. You can cough in your sleep. You guard your airway in your sleep to stop yourself choking. So, there's no reason why you shouldn't sneeze in your sleep. I just suspect that most people don't remember that they've done it.

Denny - Well, I've never heard anyone sneezing in their sleep. I've heard people coughing in their sleep.

Chris - I was going to say, how big is your sample size, Denny?

Kat - You need to sleep with some more people to find out.

Denny - I'm not going to answer that question.