Discover the Two-Shift Sleep Cycle of the Middle Ages That Might Actually Be Healthier for Us

Today, sleeping around eight hours a night is the norm, but this routine wasn’t always the case. During the Middle Ages, people often slept in two distinct shifts, known as the first sleep and the second sleep. The theory comes from Roger Ekirch, an American historian who specializes in historical sleeping habits. His book, At Day’s Close: Night in Times Past, argues that before artificial lighting, most people would go to bed around sunset and wake up again around four hours later.

Historians like Ekrich discovered mentions of biphasic sleep in journals, literature, and medical writings from the 15th to the 18th centuries. It was considered a natural and healthy sleep pattern, influenced by the natural rhythms of day and night. From around midnight until the early hours of the morning, people would wake up to read, pray, or even socialize. Then, they would head back to bed for their second sleep from around 3 an.m. until daylight.

Although historians believe this nocturnal routine was common during that time, it wasn’t for everyone. “Not everyone, of course, slept according to the same timetable,” Ekirch explains. “The later at night that persons went to bed, the later they stirred after their initial sleep; or, if they retired past midnight, they might not awaken at all until dawn.”