Typical sleep patterns of one big block of 6 to 9 hours with no naps is usually referred to as monophasic sleep. A second natural sleep pattern is biphasic sleep which breaks up your sleep into two chunks (Wehr, 1992; Ekirch, 2001). My question concerns polyphasic sleep which partitions your sleep in 3 or more periods during the day.
From personal experience (and anecdotal evidence; this is a popular blogging topic), I know that the first one to two weeks of trying to keep a difficult polyphasic sleep schedule (say uberman that divides your day into 6 evenly spaced half-hour naps) produces very low performance. At first you are unable to fall asleep and you need your alarm clock to wake up and you feel groggy, agitated and slow. However, after the first week, a lot of these negative effects seem to disappear as you grow accustomed to the schedule. You start to get very vivid dreams during your naps (and I started to wake without the need for alarm clock) suggesting REM sleep. However, I have never subjected myself to proper performance tests while attempting polyphasic sleep.
What are the medium term (more than 2 weeks, less than a year) effects of polyphasic sleep on performance of tasks like working memory, reading speed and comprehension, and IQ tests?
Unfortunately, most sleep studies are less than two weeks in duration and report the obvious negative effects; except on working-memory which benefits from naps. Alternatively, they are military studies that only track vigilance (not having micro-sleeps)(Porcu et al., 1998; Rhodes & Gil, 2003) , or have physical measures of no interest to me (Stampi, 1989).