Posted on Mon, 22 Jun 15
By comparing sleep patterns of traditional people living without electricity with a modern village, electric lighting has been linked to worse sleep in a natural setting, for the first time.
Light pollution and light emitting electronic devices are well known to disrupt sleep but much of the research making this connection has been experimental or by association.
To better demonstrate a link a research group compared the sleep patterns in different communities of the Toba/Qom, historically hunter-gatherer indigenous people in the Argentinean Gran Chaco region of northeastern Argentina. These communities share the same ethnic and sociocultural background, but some have free access to electricity while the others rely exclusively on natural light.
The researchers found that access to electricity was associated with later bedtimes and sleep onsets leading to shorter daily sleep duration than in individuals without access to electricity, which equated to approximately 40-min less sleep in summer and an 1-hour less in winter.
“Our study shows that the presence of electricity reduces sleep—a salient trait in human biology—in a traditionally hunter-gatherer group, a condition that represents a proxy for the human ancestral sleep-wake cycle,” commented the investigators.
"Importantly, the Toba/Qom community with access to electricity that we studied has remarkably less access to brightly artificially lit environments, appliances, eReaders, and sources of mass media than typical communities in industrialized societies; thus, the reduction of sleep we report likely underestimates the effect of electricity on human sleep.”
de la Iglesia HO, Fernández-Duque E, Golombek DA, Lanza N, Duffy JF, Czeisler CA, Valeggia CR. Access to Electric Light Is Associated with Shorter Sleep Duration in a Traditionally Hunter-Gatherer Community. J Biol Rhythms. 2015 Jun 18. pii: 0748730415590702. [Epub ahead of print]