It is very real -- I am living proof. :) I choose my own hours for work, and often sleep twice, and my rhythm varies between being awake during the night and the day. I do think that not everybody is like this though.
Sometimes ones own anecdotes are sufficient proof. Gathering facts and compiling statistics may be necessary from an outsider's perspective, but for some things a single personal experience is enough.
I also pick my own hours for work, and for the last few years have woken up after 4-5 hours of sleep, worked for a couple hours, then gone back to sleep for another few hours, very much like in the monastery schedules mentionned upthread (and getting a lot of good work done, I might add).
Will a sufficient amount anecdotal evidence turn into proof?
In any case, I was getting worried that too much coding had destroyed my health, it turns out I am may have gone back to sanity instead; the article certainly made my day.
