You can’t smell while you’re asleep

And that should have you running to buy a smoke detector if you don’t already have one!
I was listening to the Brainscience Podcast this morning; The ‘smell’ episode. This is something I found out which is worth repeating here as it’s relevant to all our safety. You might think that you’ll smell the smoke and wake up in time, but there’s a good chance you won’t. So for your own sake, make sure you have smoke detectors installed and working. Test them regularly. Change the batteries when needed. Even consider getting one with a Carbon Monoxide detector included – because you won’t smell that even when you’re awake!

I smell the coffee every morning

Yes, I can hear your objection! And it’s true – you do smell the coffee, or someone cooking breakfast for you, or whatever. So let’s explain a little more.
There are 4 types of sleep – called N1, N2, N3 and REM (that’s as technical as we’ll go here – see the wiki for more details). Early in your sleep, and again as you get to waking up (N1 & N2) you can smell. In N3 & REM stages (deep sleep and dreaming) you can’t smell anything in the outside world. It’s been tested with some pretty nasty smells too.

4 ‘dead’ hours

Now depending on how you sleep, how often the kids/partner wake you, how long you get in bed, etc… the deep & dreaming sleep stages could be up to half of your night. If you get the healthy 8 hrs, then that’s about 4 hrs in which you won’t be able to smell anything – no smoke, no skunk, nothing.
Four hours in which a dead battery could cause a dead you – have you checked yours recently?