Plus, it is most probably harmful: http://www.supermemo.com/articles/polyphasic.htm

Maybe the author was talking about biphasic sleep (a smaller core night sleep with a big siesta)?

In the article I'm talking about biphasic sleep. I think it's still a category of polyphasic sleep, but if I'm wrong I'll edit the article.

I don't know for sure if you are wrong. Just that according to this article[1], our circadian rhythm makes us sleepy twice a day: at night, and, to a lesser extent, around midday. So it make sense to sleep at both times. Real polyphasic sleep goes again that cycle, and that makes it fundamentally different from biphasic sleep.

Now, real polyphasic sleepers don't agree "real" polyphasic sleep is actually harmful. At this point, I am not so sure, and therefore tend to be conservative. I would love to see systematic, long experiments (not just experiences) about polyphasic sleep.

[1]: http://www.supermemo.com/articles/sleep.htm

Rebuttal to aforementioned article: http://www.puredoxyk.com/index.php/2006/11/01/an-attack-on-p...

(copy-paste from my comment on the "How to nap..." article)