Why Do We Sleep Under Blankets, Even on the Hottest Nights? (2017) (opens in new tab)

> "I barely know what a BTU is"

Neither does anyone else, its one of those archaic units that changes slightly based on who is using it and hangs on in oil and gas industries, and also air conditioners and heaters.

It was defined as the amount of energy to raise one pound of water by one degree Fahrenheit at one atmosphere of pressure, but that amount of energy depends on the starting temperature of the water, and different things use different starting points, so it ranges from about 1054 to 1059 joules

https://en.wikipedia.org/wiki/British_thermal_unit

'Go Wild' (John Ratey, Richard Manning) theorizes that the modern concept of bedrooms in which we segregate ourselves to sleep is a mismatch with our evolutionary established state. We would naturally lie in very close proximity of tribe and family for heat, contact and security. Sleeping and resting on one another out in the open. Perhaps pillows and blankets (esp weighted) serve as a proxy for this, not just temperature?

Is this a common thing? Sleeping without any sort of cover during the hot summer months (notably July and August) is the norm here (North Africa) and never heard of anyone who does it (AC or not).

Is this an American thing? Do people in warmer regions of the country (Texas, Florida, ...) also feel the same?

Recently discovered that "weighted blankets" are a thing.

https://en.wikipedia.org/wiki/Weighted_blanket

They didn't include a common reason for wanting at least a thin blanket on hot summer nights: it keeps the mosquitoes away!

"Always sleep covered" Leonardo Da Vinchi (from memory of a book i read in 1990s)

I did not realize that things like sheets, blankets and pillows used to cost serious money.

Clearly for better protection against monsters