Study: Lunar Cycles Modulate Sleep

A recent paper published within the Journal Science Advances reports that the period leading up to a full moon — characterized by moon illumination after dusk —  appears to result in later sleep onset and shorter sleep duration in both rural and urban populations.

Researchers from the University of Washington, Seattle, recruited 562 subjects for the study. They enrolled 464 college students to measure the impact of the moon in artificially-lit urban settings, and 98 participants from three Toba-Qom indigenous communities in Argentina — some without any access to electricity.

The findings validate the original hypothesis: That synchronization exists between human sleep and the cycle of the moon. Those living in ingidenous communities with less access to electricity slept less and stayed up later on moonlit nights — demonstrating the contrast caused by this natural light source.

In the modern era, urbanized humans frequently expose themselves to artificial light into the evening, a behaviour known to inhibit sleep hormones and interrupt the circadian rhythm. Despite the presence of glowing devices, city-dwelling participants still experienced shifts in their sleeping patterns with the lunar phase — prompting researchers to attribute these effects to another mechanism by which the moon may influence sleep: Gravitational pull.

Indigenous humans appear to still live by the rhythms of the moon. This natural adaptation stems from the ancient utilization of periods of increased moonlight. Toba-Qom elders report particularly high increases in hunting, fishing, and sexual reproduction during periods when the moon shines brightest.

  Luke Sumpter is a freelance journalist that specializes in health, wellness, and alternative therapies. Currently, he’s working on a dissertation exploring the emerging role of the endocannabinoid system in orthopaedic medicine.