Segmented Sleep

Segmented sleep, also known as divided sleep, bimodal sleep pattern, or interrupted sleep,is a polyphasic or biphasic sleep pattern where two or more periods of sleep are punctuated by a period of wakefulness. Along with a nap (siesta) in the day, it has been argued that this is the natural pattern of human sleep. A case has been made that maintaining such a sleep pattern may be important in regulating stress.

Historian A. Roger Ekirch (2001,2005) argues that before the Industrial Revolution, segmented sleep was the dominant form of human slumber in Western civilization. He draws evidence from documents from the ancient, medieval, and modern world, which he discovered over the course of sixteen years of research. Other historians, such as Craig Koslofsky, have endorsed Ekirch's discovery and analysis.