Humans May Not Be Naturally Wired for Continuous Sleep, Historical Evidence Suggests

Waking up in the middle of the night, only to stare at the ceiling, might be a more natural human behavior than commonly believed. Historians and sleep scientists are increasingly finding evidence that suggests humans historically slept in two distinct phases, a pattern that modern bodies can easily slip back into.

This historical sleep pattern, often referred to as "first sleep" and "second sleep," involved an initial period of sleep followed by a waking interval of a few hours before returning to sleep. This contrasts sharply with the modern ideal of a single, consolidated block of sleep throughout the night.

The research indicates that this segmented sleep was common for centuries, potentially influenced by environmental factors like natural light cycles and social practices. The idea that continuous sleep is the only normal or healthy way to sleep is a relatively recent concept, challenged by this growing body of historical and scientific evidence.