This is interesting for truly unbearable summer nights:
https://www.sleep.org/articles/could-the-egyptian-method-improve-your-sleep/
I’m guessing sleeping on wet sheets in Egypt (or the SW desert) would be effective. Everywhere else where it is 60%+ humidity levels it would make it worse.
And these guys in D.C. are idiots. Keep the house at 82 degrees at night!!?? Heck if I’m going to turn on the heat in the middle of August! (73 with a nice breeze at the moment! Seattle.)