As a narcoleptic, I am always suspicious of extreme polyphasic sleep claims. Biphasic seems to be natural, but anything like the uberman schedule seems to conflict with what I know about narcolepsy.

The primary symptom or possibly the primary cause of narcolepsy is skipping straight from light sleep to REM within minutes of falling asleep. When I was tested, I entered REM between 3 and 7 minutes of falling asleep. Sleep cycles are fractured and slow wave sleep is reduced or skipped entirely.

By contrast, a normal person enters REM after usually more than an hour, stopping along the way in three different phases of sleep. The deepest stage, slow wave sleep, is where quite a lot of brain repair occurs. Glial cells are restored, free radicals are cleared out, glucose is stored in the brain. Growth hormones repair tissue damage.

Many of the claims of ubermen proponents seem to rest on entering REM almost immediately after staring a nap. Much like a narcoleptic. Stage four is arguably more important for mental health, but this stage is not mentioned by proponents that I have seen. Furthermore, some of the symptoms of narcolepsy seem to match the experiences of polyphasic sleepers, particularly the general awakeness/non-grogginess which is occasional unexpected and uncontrollably strong daytime sleepiness.

Background: The idea of less sleep super appeals to me because I need so much. Before I was diagnosed I tried Uberman but it didn't seem to reduce my daily hours of sleep needed, and in retrospect it obviously could never have done that for me. But my natural sleep cycle is super polyphasic, 3 or 4 naps a day and reduced sleep at night. Unfortunately, my body wants is 10+ hours regardless of whether its in one chunk or spaced out throughout the day, and spacing seems irrelevant since I rarely have SWS regardless.