I have misgivings about polyphasic sleep cycles. From what I've read biphasic is best, but even then you are still getting 7-8 hours of sleep per day.

Polyphasic sleeping is way popular these days because internet geeks all have a common vested interest in finding ways to defeat sleep forever (caffeine, anyone?), so it gets tons more hype than maybe it deserves. This website has a lot of good counterevidence for why polyphasic sleep probably won't work for you long-term. If you go and read polyphasic blogs (as the site notes), it's really true that common threads start appearing: the dreadful difficulty of it (you never entirely adapt), feeling like you have to exercise and 'do things' to keep awake, and generally just kind of zombie-ing out, no matter how long the effort made. I've read Pavlina's blog and I know he's kind of the figurehead for the entire 'movement,' but one manic, oppressively self-motivated man does not good evidence make.

Good luck anyways, though, since like everyone else I'd love polyphasic sleeping to be a viable life(sleep?)style, but I just don't think it is.