[khedoros1]

Without electrical lighting and such, I'd agree. Sleep not long after sundown, a mid-night period of wakefulness, wake up for the day around sunrise. Ever since I can remember, my own default is to maintain activity late into the night, and then sleep as close to 8 or 9 hours as I'm permitted. Granted, that's a little rough if my 3 year old happens to wake up at 7:30, but 8:30 or 9 is pretty common for him; at 1, he often slept until 10, after being put to bed at 8pm.

8:30 - 10:00 seems to be the time range that I'll be ready to get up, when left to my own schedule. It's usually 2-3 hours after I wake up that I'm really ready to jump into a heavy project. The person who wakes up at 6 is right on target to start working, if they come in at 8. Me, I always feel like I could've used a couple more hours of sleep, even if I went to bed at 10pm the night before.