People have long thought the moon had an impact on moods, disasters, and accidents. Many would blame the moon for increased fighting or strange behavior in people. A new study from the University of Washington has been published that found the moon can also impact sleep. The researchers from the University of Washington worked with scientists from the National University of Quilmes in Argentina and Yale University to investigate sleep cycles in humans.
The researchers found sleep cycles in people oscillate during the 29.5-day lunar cycle. In the days preceding a full moon, people go to sleep later in the evening and sleep for shorter periods of time. Variations were observed in both time of sleep onset and duration of sleep in both urban and rural settings.
The observations were made in various people in different environments ranging from indigenous communities in northern Argentina to college students in Seattle, Washington. The sleep cycle variance was the same no matter what access to electricity the people had though variations are less pronounced in individuals in urban environments. Researchers believe that the ubiquity of the pattern could indicate that the natural circadian rhythms are synchronized to the lunar cycle phases.
Sleep patterns among 98 individuals living in a trio of Toba-Qom Indigenous communities in the Argentine province of Formosa were recorded using wrist monitors. Communities used in the study differed in their access to electricity during the study. One rural community had no electricity, a second community with limited electricity access, and a third community was located in an urban setting with full access to electricity. Sleep data was collected from 1 to 2 lunar cycles.
Participants in all three communities showed the same sleep oscillations as the moon progressed through its 29.5-day cycle. Depending on the community, the amount of sleep varied across the lunar cycle by an average of 46 to 58 minutes in bedtimes changed by around 30 minutes. People typically had the latest bedtimes and the shortest amount of sleep in the night’s 3 to 5 days before the full moon. The same oscillations were found in data from 464 Seattle area college students.