The relationship between human behavior and the phases of the moon has long been the stuff of legend and folklore. Werewolves aside, cultures throughout history have paid great attention—and celebration—to lunar phases. Beliefs about a connection between some of our most basic biological processes—including sleep—have also been common. But, scientific evidence showing connection between human sleep and lunar cycles? That’s not something we’ve seen.
Swiss scientists conducted a study that suggests sleep is significantly affected by lunar phases. Their results show changes to sleep throughout the moon’s 29.5-day cycle, and significant increases to sleep disruption during the time immediately surrounding the full moon.
The story of how these results came to be is almost as interesting as the findings themselves. The conditions of the experiment—which was conducted by scientists at Switzerland’s University of Basel—were well suited to isolating a possible relationship between lunar phases and sleep. During study periods, volunteers slept in a highly controlled laboratory environment, which removed them from any direct visual contact with the moon, and controlled exposure to nighttime light. They were given no indications about time of day.