If you've ever slept in a hotel, gone camping, or even slept over at a friend's pad, chances are you've woken up the next day feeling groggy and bleary-eyed. Even if you don't remember tossing and turning, you probably felt pretty tired the next day. Well, that's because nature dies hard.
https://www.popsci.com/your-brain-stays-half-awake-when-you-sleep-in-new-place
https://www.popsci.com/your-brain-stays-half-awake-when-you-sleep-in-new-place