What Did Ancient Humans Do When They Couldn't Sleep?

What did ancient humans do when they couldn't sleep? Why do you wake up at 3 a.m.? Did ancient humans really sleep in "two shifts" — or ten perfect hours? Scientists put sleep sensors on people living without electricity, and the answer surprised everyone. In this video we look at what human sleep really looks like without lamps, screens or alarms — and what that means for your nights. Every claim in this video is based on published research. All sources are listed below so you can check them yourself. ⏱ CHAPTERS 00:00 3:07 a.m. — is your sleep broken? 00:50 The experiment that stopped guessing 02:01 How long do they really sleep? 02:46 The natural clock nobody talks about 03:30 One night around the fire 05:10 The truth about "two sleeps" 07:09 The night watch: 18 minutes 08:20 A world without insomnia? 09:14 The villain: electric light 12:21 What you can borrow from those nights 13:42 When to get help 14:21 Back to 3:07 📚 SOURCES 1. Yetish G, Kaplan H, Gurven M, et al. (2015). Natural sleep and its seasonal variations in three pre-industrial societies. Current Biology 25(21):2862–2868. [OBS] https://www.cell.com/current-biology/... 2. Wiessner PW (2014). Embers of society: Firelight talk among the Ju/'hoansi Bushmen. PNAS 111(39):14027–14035. [OBS] https://www.pnas.org/doi/10.1073/pnas... 3. Ekirch AR (2001). Sleep we have lost: pre-industrial slumber in the British Isles. American Historical Review 106(2):343–386. [REV — historical] https://sites.google.com/vt.edu/roger... 4. Wehr TA (1992). In short photoperiods, human sleep is biphasic. Journal of Sleep Research 1(2):103–107. [EXP] https://en.wikipedia.org/wiki/Thomas_... 5. Boyce N (2023). Have we lost sleep? A reconsideration of segmented sleep in early modern England. Medical History. [REV — historical] https://www.cambridge.org/core/journa... 6. Samson DR, Crittenden AN, Mabulla IA, Mabulla AZP, Nunn CL (2017). Chronotype variation drives night-time sentinel-like behaviour in hunter–gatherers. Proceedings of the Royal Society B 284:20170967. [OBS] https://royalsocietypublishing.org/rs... 7. de la Iglesia HO, et al. (2015). Access to electric light is associated with shorter sleep duration in a traditionally hunter-gatherer community. Journal of Biological Rhythms 30(4):342–350. [OBS] https://washington.edu/news/2015/06/1... 8. Wright KP Jr, et al. (2013). Entrainment of the human circadian clock to the natural light-dark cycle. Current Biology 23(16):1554–1558. [EXP] https://www.sciencedaily.com/releases... 9. Chang AM, Aeschbach D, Duffy JF, Czeisler CA (2015). Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. PNAS 112(4):1232–1237. [EXP — controlled crossover] https://www.pnas.org/doi/10.1073/pnas... 10. CDC / NCHS (2025). Short sleep duration and sleep difficulties among adults: United States, 2024. NCHS Data Brief No. 559. [OBS] https://www.cdc.gov/nchs/products/dat... 11. Qaseem A, et al. (2016). Management of chronic insomnia disorder in adults: a clinical practice guideline from the American College of Physicians. Annals of Internal Medicine 165(2):125–133. [REV — guideline based on RCTs] https://www.acponline.org/acp-newsroo... ⚠️ This video is for educational purposes only and is not medical advice. If poor sleep is affecting your health, mood or safety, talk to a doctor or a sleep specialist. #sleep #insomnia #history #anthropology #science #circadianrhythm #ScribbleWhy