Why Humans Are Supposed to Sleep in Two 4-Hour Phases

Summary by Krater

This video examines the history of human sleep patterns, explaining how pre-industrial societies practiced biphasic sleep rather than the modern eight-hour consolidated sleep pattern.

From the video

Answers: Why did people used to sleep in two segments?

• biphasic sleep
• historical sleep patterns
• pre-industrial sleep
• polyphasic sleep
• sleep history

What it concludes

• Pre-industrial western society practiced biphasic sleep, waking for a period in the middle of the night.
• Biphasic sleep is supported by both historical records and experimental research.
• Biphasic sleep may be the natural human sleep pattern.
• The modern consolidated eight-hour sleep pattern became widespread due to the industrial revolution, artificial lighting, and urban development.