I usually have to wake up 5:30am or so for military pt and then I have a full day of classes. I try and take a nap around 6 or so, b/c otherwise I'm dead when I'm trying to do work or if I have a fraternity event.
During the summer I have sort of the same deal. I wake up at 6 or so and go to work, I'm done by around 4ish. Then I sleep for a few hours and go out to the bars until 3 or so in the morning. It works pretty well.
Threaded Mode