Pitch black. That was the default for most of human histo...
“Pitch black. That was the default for most of human history. No streetlights bleeding through curtains. No digital clock glowing from the dresser. No charging light blinking in the corner. Just darkness — the kind the body was built to sleep inside. Now even our "dark" rooms aren't dark. There's always something on. Always something glowing. We didn't just change the light outside. We brought it into the one place the body was supposed to finally switch off.”
Summary
Before electric lighting, humans typically slept in complete darkness, often with segmented sleep patterns documented in pre‑industrial and medieval societies. Today, artificial light sources such as screens, clocks, and chargers are common in bedrooms and are linked to shorter, poorer‑quality sleep. The passage’s contrast between historic darkness and modern light‑filled rooms is supported by current research.
Sources 59 searched
- Association between exposure to light at night (LAN) and sleep problems: A systematic review and meta-analysis of observational studies - ScienceDirect
Higher LAN exposure was associated with a 22 % increased prevalence of sleep problem. ... Keeping bedroom dark at night may be an important strategy for reducing sleep problem risk.
- Natural light control to improve awakening quality - ScienceDirect
Nighttime light pollution negatively impacts sleep and awakening quality [64]. Over 80% of the world's population, and 99% of the population in the West, live under light pollution [41]. Nighttime light pollution is associated with complications ...
- Light exposure behaviors predict mood, memory and sleep quality | Scientific Reports
Ample research has shown that light influences our emotions, cognition, and sleep quality. However, little work has examined whether different light exposure-related behaviors, such as daytime exposure to electric light and nighttime usage of gadgets, especially before sleep, influence sleep ...
- Access to Electric Light Is Associated with Shorter Sleep ...
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- Natural sleep and its seasonal variations in three pre-industrial societies - PMC
Light has been shown to be a major factor in human sleep and circadian rhythm control, partially mediated by light’s effects on the melanopsin system[19, 26–28]. Consistent with this, we show here that sleep occurs almost entirely during the dark period in these traditional societies.
- The forgotten medieval habit of 'two sleeps'
After an initial week of observing ... the usual 16 hours to just 10. The rest of the time, they were confined to a bedroom with no lights or windows, and fully enveloped in its velvety blackness....
- The myth of the eight-hour sleep - BBC News
In the early 1990s, psychiatrist Thomas Wehr conducted an experiment in which a group of people were plunged into darkness for 14 hours every day for a month. It took some time for their sleep to regulate but by the fourth week the subjects ...
- Roger Ekirch - Sleep Research
Science of Us points to historian Roger Ekirch who says that patterns from people in early modern Europe and North America that show that humans slept in a “dead” and “morning” shift.
- History of Sleep – How Ancient Humans Slept Before Electricity - Sleep Advisor
With historical documentation of early hunter-gatherer and agricultural societies limited, researchers have looked to present-day communities living in similar ways to assess the sleep habits of ancient civilizations.
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