Polyphasic sleep is when the standard overnight sleep period is broken up into shorter periods arranged across the 24-hour clock. In general, more than two periods per day are spent sleeping. The precise timing of these periods is not critical, and there have been multiple patterns devised to shorten the amount of sleep needed or increase productivity. It may also be desired in those who do shift work. One of the most common polyphasic patterns is called the Uberman sleep schedule, in which 20-minute naps occur every 4 hours. As a result, there are only 2 total hours of sleep in every 24 hours.
This multiple napping schedule may not ultimately be plausible. The body’s natural clock reinforces sleep during the night with the release of the hormone melatonin. This establishes the circadian rhythm. This pattern may not always match darkness, however, with variations resulting in circadian rhythm sleep disorders. One of these disorders resembles polyphasic sleep. It is called the irregular sleep-wake rhythm and is seen in people with head injuries or dementia. Therefore, the only natural pattern that resembles polyphasic sleep in humans is a marker of grave dysfunction.
Furthermore, although it may seem advantageous to decrease the amount of time spent sleeping, if you do not meet your sleep needs, you are likely to face the consequences of sleep deprivation. These can be a relatively mild nuisance but may prove fatal. In addition, dividing sleep periods in this way may significantly diminish the quality of the sleep that you obtain.
It is therefore not recommended that people sleep in a polyphasic manner.