Would you pardon me while I expound on a theory?
When I was young there was no synthetic bedding.
One had two to three wool blanket on the bed over a sheet. One then had one or two comforters made of heavy cotton batting with duvet covers. Weighed pounds!
If it was really cold parent used to put a crotchet woool blanket or two on top of the whole mound.
Kids were pressed as tightly as pancakes.
When I was ten the family switched to synthetic “puffs”. Boy it was hard to sleep without all the pressure.
My ADD kids sleep best with heavy blankets, woollies when I can get them. Many ADD and ADHD kids use weighted blankets to sleep well.
My theory is that northern cold weather kids have had an increase in behavioral issues due to the lack of pressure while they sleep. Aspberger kids even more so.
Interesting.
I’ve noticed I can’t stand modern puffy comforters unless I throw a heavy blanket on top of them. If I get too warm I just let my feet hang out.