Humans can adapt to sleeping in cool environments.

“And we just said that people can adapt to sleeping cool. These are like the aboriginal studies that were done. And I think in the '30s or whatever, where they took literally refrigerated trucks in Australia, took the natives, who by culture they sleep under 30-degree temperature. No covers, no blankets, they shiver all night. And they get perfect REM sleep. And yet, the Caucasian control, those guys were just miserable and they were horrible. The same thing with the Lapps, you know. They could learn to sleep in these cold, just on a little cot above the floor. The ice hut, and they were getting amazing sleep even though it was cold. And they weren't all blanketed, you know.”