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On the cusp of the change to Daylight Saving Time, a recent journey from California to Vermont revealed the disorienting effects of crossing multiple time zones. Arriving just before midnight, the clock leapt forward an hour at 2 a.m., heightening feelings of disarray.
In discussions with sleep researcher and evolutionary anthropologist David Samson, it became apparent that the resulting jet lag was not merely a temporary issue. It masked deeper, chronic disruptions in sleep regulation. Historically, human beings aligned their waking and sleeping patterns with natural light cycles, driven by environmental factors like daylight and temperature. However, modern lifestyles have shifted dramatically, often leading to excessive indoor time and exposure to artificial lighting, which can desynchronize our internal body clocks, known as circadian rhythms.
Samson describes this modern state as akin to being trapped in a "circadian jail cell." He explains that our physiology relies heavily on the data provided by our environment. Interference with these cues hampers essential bodily functions, including hormone regulation. Circadian misalignment is associated with numerous health issues, including depression, various cancers, cardiovascular diseases, and heightened inflammation.
A recent review of over 5,100 individuals from 21 countries—published in Proceedings of the Royal Society B—underscored a concerning trend: while people in industrialized nations average around 7.1 hours of sleep each night, they often do so at times that conflict with their natural body rhythms. In contrast, communities in nonindustrialized regions, living without access to electricity, averaged 6.4 hours of sleep but adhered more closely to the sun’s schedule, suggesting a healthier synchronization with their biological clocks.
Not all researchers agree with this perspective. Neuroscientist Horacio de la Iglesia argues that the traditional foraging societies referenced in Samson’s studies may not represent the full spectrum of possible sleep patterns. His research indicates that those living in environments devoid of stressors tend to sleep more, potentially averaging up to nine hours a night. He posits that the introduction of electricity alters sleep habits significantly; as communities gain access to electric lighting, sleep durations often decrease. This change can lead to a mismatch between the circadian clock and work schedules, depriving individuals of sleep.
De la Iglesia advocates for adaptations within society, such as allowing more flexible work or school hours, enabling people with late bedtimes to wake at reasonable hours without issue.
Despite the ongoing debate, Samson emphasizes the importance of recalibrating one’s internal clock. He advocates for "chronohygiene," which encourages creating indoor environments that mimic natural conditions. This could include adjusting thermostats to maintain cooler temperatures at night and utilizing lighting that simulates natural daylight cycles.
Furthermore, time-use expert Juana Lamote de Grignon Perez of University College London highlights that concerns about blue light from electronic devices may be overstated, suggesting that a brief morning stroll significantly impacts body rhythms more than prolonged screen exposure.
Nonetheless, it remains prudent to limit late-night screen time, as engaging with devices in bed might have broader effects on overall sleep quality.
Source
www.sciencenews.org