Werewolves, tides, and sleep? The influence of the moon—mythical and real—has long been the subject of science and folklore. Researchers at the University of Washington, the National University of Quilmes in Argentina, and Yale University set out to determine if sleep cycles seemed to change with the lunar cycle.
According to a summary of the study (which originally appeared in the journal Science Advances) in Space.com, researchers found that in the days leading up to a full moon, people tended to sleep later and sleep for fewer hours.
“For this work, the team studied college students in the city of Seattle, Washington, and also with those living in indigenous communities in northern Argentina, two different environments where there is a variety in individual access to electricity because of how artificial light might affect the participants,” writes Chelsea Gohd.
Using sleep-monitoring wrist devices, they studied 98 individuals living in three indigenous communities in Argentina, plus data from 464 college students in Seattle. According to Gohd, “The team found that, while the connection between sleep cycles and lunar cycles is a bit more obvious in communities without electricity access, the connection still seems to be present in areas with electricity as well.”
“We see a clear lunar modulation of sleep, with sleep decreasing and a later onset of sleep in the days preceding a full moon,” lead author Horacio de la Iglesia, a professor of biology at the University of Washington, said in a statement. “And although the effect is more robust in communities without access to electricity, the effect is present in communities with electricity, including undergraduates at the University of Washington.”