Before electric light redefined the rhythm of the night, biphasic sleep was humanity’s biological norm.
This interval, referred to in ancient texts as the dorveille, was not seen as a frustrating interruption or a symptom of insomnia. It was, rather, a quiet period of two or three hours.
Some used it for domestic tasks. Others for conversation. Many for prayer. Others for intimacy, since the fatigue of the day had passed.
Roger Ekirch and the Industrial Disruption of Rest
After decades of research, historian Roger Ekirch uncovered a reality in archival records that now feels foreign to us: biphasic sleep was the dominant form of rest for millennia.
Ekirch traced the practice back through a remarkable span of history, locating some of the earliest references in the eighth century B.C., within the verses of the Odyssey. From Homer’s epic to the dawn of the 20th century, humanity followed this natural rhythm, inherited from prehistoric ancestors.
Far from being an anomaly, fragmented sleep was a universal custom. It began to fade only with the arrival of industrialization. Almost imperceptibly, the spread of electricity erased a habit that had been with us since the dawn of our species.
The decline of this system was not abrupt. It was a gradual erosion, driven by urbanization. The arrival of public lighting and the ability to light up homes at will proved to be the turning point. Night was no longer a refuge — it became an extension of the workday.
The incandescent bulb did more than push back the darkness. It compressed the “first” and “second” sleep into a single, consolidated block. Slowly, the rhythms of modern life took shape.
Today, waking in the middle of the night is often seen as a malfunction, an anomaly labeled insomnia. Yet in the stillness of that nocturnal awakening, we may not be facing a disorder, but a biological echo of who we were for thousands of years.
To rediscover biphasic sleep is, ultimately, to recognize that our nature carries rhythms electricity has never fully erased.
