HomeScienceScience behind why humans stopped sleeping twice every night

Science behind why humans stopped sleeping twice every night

Historical evidence reveals that humans once slept in two nightly phases, a practice now vanished due to modern lighting and lifestyle changes.

November 06, 2025 / 10:47 IST
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Humans Once Slept Twice a Night (Image: Canva)
Humans Once Slept Twice a Night (Image: Canva)

For centuries, humans naturally slept in two distinct nightly segments, but later this pattern got vanished. This study highlights how artificial light and modern schedules disrupted this natural rhythm. Understanding this pattern sheds light on middle-of-the-night awakenings today.

Eternal awakenings, split slumber

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It was common practice that humans take two separate naps within a night. The initial rest came soon after the sun went down and it was many hours in duration. After this period of awakening, second sleep ensued until the morning sunlight came.

This trend existed throughout Europe over centuries which are captured in the diaries. Sleep was naturally biphasic and socially accepted during the pre-industrial era.