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Bed and rise times during the Age of Enlightenment: A case report
Author(s) -
van Egmond Lieve,
Ekman Martin,
Benedict Christian
Publication year - 2019
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1111/jsr.12862
Subject(s) - sunset , sunrise , wakefulness , enlightenment , sleep (system call) , duration (music) , climatology , history , demography , meteorology , geography , environmental science , psychology , geology , art , electroencephalography , sociology , philosophy , physics , theology , literature , astronomy , psychiatry , computer science , operating system
Studies have shown that our modern electrical lighting environment reduces naturally occurring seasonal variations in sleep–wake rhythms, such as longer sleep during the winter versus summer. However, less is known about how timing and duration of sleep were affected by the seasons in the premodern era, before the invention of electrical lighting. The Swedish researcher Olof Hiorter collected and documented geophysical data every hour during wakefulness in Uppsala, Sweden, between December 1746 and November 1747. In this way, his bed and rise times could be approximated. The data revealed that Hiorter's rise times occurred around 1 hr before sunrise in winter versus 1 hr after sunrise in summer. No such association was observed between the time of sunset and Hiorter's bedtimes. Finally, the time in bed was about 3.5–4 hr shorter in summer compared to winter. This 273‐year‐old case report suggests that time in bed and rise times of people from the premodern era exhibited seasonal variations.