Next time you’re tossing and turning, unable to get to sleep, have a look out the window. You might just see a big fat full moon staring back at you.
A new study—that is, a new look at an old study—has drawn a correlation between the full moon and sleep patterns, a paper published in Current Biology announced this week. It seems that among other things the moon influences our bodies’ creation of melatonin, which modulates sleep.
During a full moon, 30 test subjects whose brain patterns, eye movements and hormone secretions were monitored demonstrated that sleep quality was actually altered by the lunar cycle, reported a group of scientists at the Psychiatric Hospital of the University of Basel in Switzerland. The volunteers were studied over three years.
“Around full moon, brain activity in the areas related to deep sleep dropped by 30 percent,” the university said in a press release. “People also took five minutes longer to fall asleep and they overall slept for 20 minutes less. The volunteers felt as though their sleep had been poorer during full moon and they showed lower levels of melatonin, a hormone that regulates sleep and wake cycles.”
Thus humans joined the legions of other animals on both water and land whose behavior may very well be aligned with the moon. While circadian rhythms are long-established, circalunar rhythm has not been till now.
“This is the first reliable evidence that lunar rhythm can modulate sleep structure in humans,” said Christian Cajochen, the University of Basel chronobiologist who led the research team, in the statement.
Although he told National Geographic that there were other possible explanations for the findings, his team surmised that these circalunar rhythms could be a holdover from ancient days, when people’s behavior needed to be synchronized by the moon. Even today, the menstrual cycle is testament to the power of the moon on the human body. And, as Time magazine pointed out, the electrochemistry of the brain changes in people with epilepsy around the time of a new moon, increasing their chance of seizures.
It’s a conclusion that almost escaped the researchers on first pass. The data was mined from another research project conducted in 2000 that was not examining the effect of the moon per se, and it didn’t immediately occur to them to analyze the data in terms of lunar phase.
"We just thought of it after a drink in a local bar one evening at full moon, years after the [original] study was completed," the authors wrote, according to National Geographic.
Electric light and other facets of contemporary life had been masking this phenomenon, the researchers suggested. But the results held firm even when these factors were filtered out.
"The subjects were sleeping in windowless rooms, and although they may have been aware of the phases of the moon, neither they nor even the investigators knew that lunar phase would be a parameter that would be considered in the study," said Malcom von Schantz, a sleep and circadian researcher at the University of Surrey in the U.K., in an interview with National Geographic. Though not involved in this study, he called the results “fascinating” and said that the fact that the researchers discovered the link almost by accident lent credence to the findings, even though previous studies have found no such link.