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.