Biology professor Horacio de la Iglesia and postdoctoral researcher Leandro Casiraghi were featured in a UW News article on their new research into the effects of moon phases on human sleep patterns.

For centuries, humans have blamed the moon for our moods, accidents and even natural disasters. But new research indicates that our planet’s celestial companion impacts something else entirely — our sleep.

In a paper published Jan. 27 in Science Advances, scientists at the University of Washington, the National University of Quilmes in Argentina and Yale University report that sleep cycles in people oscillate during the 29.5-day lunar cycle: In the days leading up to a full moon, people go to sleep later in the evening and sleep for shorter periods of time. The research team, led by UW professor of biology Horacio de la Iglesia, observed these variations in both the time of sleep onset and the duration of sleep in urban and rural settings — from Indigenous communities in northern Argentina to college students in Seattle, a city of more than 750,000. They saw the oscillations regardless of an individual’s access to electricity, though the variations are less pronounced in individuals living in urban environments.

The pattern’s ubiquity may indicate that our natural circadian rhythms are somehow synchronized with — or entrained to — the phases of the lunar cycle.

“We see a clear lunar modulation of sleep, with sleep decreasing and a later onset of sleep in the days preceding a full moon,” said de la Iglesia. “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.”

Read the full story in UW News.

Bonus: See related stories in CNN, The Guardian and HealthDay