Polyphasic sleep - Wikipedia, the free encyclopedia

Polyphasic sleep is a sleep pattern specification intended to reduce sleep time to 2–5 hours daily. This is achieved by spreading out sleep into short naps of around 20–45 minutes throughout the day. This is supposed to allow for more waking hours with relatively high alertness.
The method uses natural human sleep mechanisms to maximize alertness when sleep time needs to be minimized. However, it requires a rigid schedule which makes it unfeasible for most people. It can work well for those engaged in activities which do not permit lengthy periods of sleep.

Read more