A term often related to long distance, thru hikers, but also applying to the shorter hikes. Hikers will often go to bed much earlier than when they are at home particularly during the colder, darker months and will often get up early as well. In my case it’s not unusual to be in my sleeping bag going to sleep by 7:30pm and as such 9:00 pm is often the middle of the night for many keen hikers.