I really have a hard time buying into these sorts of studies. That goes for almost anything related to the human body. The study[1] the poster links to consisted of eight men for two days.

The study goes on to say: "Ultradian rhythms of similar frequency were found in perceptual and motor performance. The rhythms in perception, however, were drastically modified by altering the sampling frequency and were, therefore, attributed to statistical artifact."

I guess the questions I have are: As a programmer, am I in pursuit of heightened motor skills? Is this study statistically significant?

[1]http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA296199

I think a more important advice than follow the ultradian rhythm is simply to sleep enough. The negative effects on productivity of insufficient sleep are severe but hard to recognize. It's a widespread problem, half of everyone doesn't sleep enough.

I struggle with this myself. I've noticed that if i consciously sleep in excess of 8 hours a night every night my productivity jumps, but i always tend to drift back to 7 hours sleep.