One day, last autumn, I woke up at 7AM, went to school, and after school, in the evening, went for a scout trip. We started to walk at 11:50PM, and walked the entire night, and we were driven home at 1PM the next day (slept in the car). 36 hours, eleven of them spent walking. That's the most extreme I have ever done, sleep-wise. Usually, I get up early, and get to bed early.