Why Humans Used to Sleep Twice a Night

It's 3 AM and you're wide awake again. For hundreds of years, that might have been completely normal. In 1697, a nine-year-old girl in an English court case mentioned her mother getting up after her "first sleep." Historian Roger Ekirch went on to find thousands of references to a "first sleep" and a "second sleep," with a calm hour or so awake in between. People used that time to pray, visit neighbors, read by candlelight and think about their dreams. Then artificial light changed everything, and within a few generations we forgot. We also look at the 1990s experiment that seemed to bring the pattern back, the scientists who disagree, and what it all means for you if you wake up in the middle of the night. Chapters 0:00 It's 3 AM again 0:46 The clue in a 1697 court record 2:09 How two sleeps worked 3:16 The watch: what people did at midnight 4:13 The experiment: 14 hours of darkness 5:04 What killed the second sleep 6:30 The twist: not everyone agrees 7:42 What it means for you 8:22 Team one sleep or team two sleeps? Comment below: what time did you last wake up in the night? And which team are you on? This video is for general education, not medical advice. If you have ongoing sleep problems, talk to a doctor. Sources and further reading BBC Future, "The forgotten medieval habit of 'two sleeps'" (2022), via Virginia Tech: https://liberalarts.vt.edu/news/in-th... CNN Health, "How our ancestors used to sleep can help the sleep-deprived today" (via KTVZ): https://ktvz.com/health/cnn-health/20... BBC News Magazine, "The myth of the eight-hour sleep" (includes Thomas Wehr's experiment): https://bbc.in/zEz7aG Yetish et al. (2015), "Natural Sleep and Its Seasonal Variations in Three Pre-industrial Societies," Current Biology: https://gurven.anth.ucsb.edu/sites/se... A. Roger Ekirch, "At Day's Close: Night in Times Past" (2005) All characters are original cartoon illustrations. Historical figures are shown as generic stick figures with name labels. #history #sleep #weirdhistory