Becoming a polyphasic sleeper...

[toots]

No, the general pattern of sleep regimes like this is that if your body has actually gotten enough slow wave/non-REM sleep (which is highly unlikely on 4 hours/day), you'll go into what's called "REM Rebound."

Someone who is not sleep deprived will generally need to sleep for about 40 minutes to an hour before experiencing their first REM cycle. But, wake someone every thirty minutes or so (preventing them from entering REM, while still allowing more physically restorative sleep), and REM Rebound sets in, wherein someone will be able to fall asleep and almost immediately pop into REM.

This is generally considered NOT A GOOD THING by most of the sleep researchers I've talked to, and in fact, REM Rebound is often of interest to psychiatrists looking for physical causes of problems.

Most often, a person will experience REM Rebound due to sleep apnea. Basically, your obstructed breathing wakes you briefly at close-intervals with the result that even if you do get enough sleep, you're not getting any REM.

I experience this when I fall asleep in the early-mid afternoon and almost immediately start dreaming. Really strange to have actual dreams from a 15 minute catnap.