Before artificial lighting became widespread, some Europeans followed a split sleep pattern: they went to bed after nightfall, slept for three to four hours, woke for a period, and then returned to bed until morning. Historical documents describe this kind of segmented rest, though it was not a uniform routine across society.
Historian A. Roger Ekirch has studied the practice, also known as biphasic or segmented sleep. In a 2001 essay, he argued that sleeping in two phases was common in western Europe before industrialisation. The interval between the two sleep periods could last around an hour, but schedules varied with the season, a person’s social and economic circumstances, and daily work.
People did not necessarily spend the waking interval waiting to fall asleep again. Accounts reviewed by Ekirch describe prayer, conversation with relatives or neighbours, small household tasks, quiet reflection and intimate encounters.
Limited access to light shaped daily life. Candles and oil lamps were available, but their use was constrained by the cost and supply of fuel, while winter nights could be especially long in rural areas. Household responsibilities—including caring for children or livestock and tending fires—could also interrupt sleep or shift people’s schedules.
A 1992 experiment by psychiatrist Thomas Wehr found that when volunteers were exposed to fewer hours of daylight, their sleep tended to lengthen and, in many cases, divide into two periods separated by one to three hours of wakefulness. The findings showed that a split pattern can occur under extended darkness, but did not establish that it is more beneficial, natural for everyone, or historically universal.
The historical interpretation remains contested. In a 2023 review published in Medical History, Niall Boyce questioned whether phrases such as “first sleep” and “second sleep” in older texts necessarily referred to two periods separated by a prolonged waking interval, suggesting they could have other meanings.
Sources: elDiario.es.