Why is it that most people, myself included, can very easily fall asleep in a chair, or sofa, without any kind of blanket or wrap, yet when we get in bed have to get all wrapped up in layers of blankets?
Because we are wearing less clothing.
I’m that way too.
My theory is that if you just sort of fall asleep in a chair/couch, it’s somewhat unplanned (at least for me that is.) If it’s just a little nap, it’s not essential to fall asleep, so you’re not “pressured” into falling asleep. It’s just something that sort of happens, if you’re tired enough.
When you settle down in bed for your usual night’s sleep, there’s more pressure on you to actually get some sleep. You’re used to using blankets, which is part of your nightly routine, so that helps to give your body the cue that you’re going to sleep soon.
(No cite - this is just my guess.)
It’s an individual thing, and certainly doesn’t apply to everyone. I feel overheated if I’m covered by anything at all . . . while my partner is all bundled up with a comforter, knitted cap, socks and sometimes even gloves. Occasionally, if I’m slightly chilled, I’ll put a thin sheet over me, but within a few minutes I’m kicking it off.
It might have to do with me being somewhat overweight and him being underweight.
I have trouble sleeping unless I have at least a sheet over me. I also sleep best if the room is pretty much refrigerated til you can hang beef off a rafter. I sleep with the window cracked open 4-6 inches in the winter. Drives my poor California desert rat of a husband nuts, he likes 100 degree F weather, and I am comfortable in subzero. sigh
I have a quilt on the ottoman in front of my chair so cover up when I feel a nap coming on.
In many places, it’s cooler at night than during the day, so comparing an afternoon nap in a chair with a night’s sleep in a bed isn’t really apples to apples.
I have a very hard time sleeping in anything other than a bed, though at a pinch I can sometimes pull off a semi-nap by closing my eyes in a chair or on a couch. And in bed, I often snuggle the covers much more than I get underneath 'em.