The Curious Case of Biphasic Sleep: Why Our Ancestors Slept in Two Shifts

Did you know that humans used to sleep in two shifts? A recent video by TikToker @mindofmarisa has reignited interest in the historical practice of biphasic sleep. The video cites examples from literature, such as Miguel de Cervantes' Don Quixote, and historical records from pre-industrial Europe, where a two-part sleep schedule was common. "In pre-industrial Europe, it was common for people to go to bed a few hours after dusk, sleep for about four hours, then wake up for an hour or two before going back to sleep until dawn," Marisa explains. This pattern is further supported by a 1992 experiment by psychiatrist Thomas Wehr, where participants, kept in 14-hour darkness, naturally reverted to a biphasic sleep pattern after just four weeks. The video suggests that modern lighting and social changes have altered our natural sleep rhythms. The video's engaging style and clear presentation make it a valuable resource for anyone interested in sleep science and history.