Have you ever gone camping for an extended time (week or two)? Real camping, where you don't have access to any screens, and filled with daytime activities (such as fishing or hiking)? If so do you still end up wanting to stay up till past midnight, and sleep till noon?

I've found that if there are no major artificial light sources, and if I've been outdoors active all day, I tend to want to fall asleep soon as its dark. And I wake up way earlier, soon as the daylight starts to hit the tent.