July 9, 2014
Sleep Studies Find Contradictory Results Pertaining To Lunar Cycles
Alan McStravick for redOrbit.com - Your Universe online
Ask any emergency room nurse or doctor and they will tell you that the effect on human behavior of a full moon cannot be denied. Besides anecdotal accounts of general human lunacy when the moon looms large in the night sky, there has been murmurs for some time in the scientific community that the Earth's natural satellite also affects our sleep. All studies thus far have been inconclusive.
As reported in Time Magazine and other outlets last year, researchers from the University of Basel, the Swiss Federal Institute of Technology and the Switzerland Center for Sleep Medicine conducted a study in 2000 that followed 33 volunteers over a period of three years in intermittent sleep lab study. Data variables collected in the study included brain wave activity during sleep, melatonin levels of the participants and the amount of time it took each individual to fall asleep and remain in a state of deep sleep. The original purpose of the study was intended simply to learn more about general human sleep patterns as they pertained to both age and gender.
What made last year's revelation interesting was that the Swiss researchers revisited the collected data to explain how the moon played a role in human sleep patterns. Their new findings showed people average as much as 20 minutes less sleep on nights with a full moon. Additionally, achieving sleep takes five minutes longer than normal and once asleep people tend to enjoy 30 minutes more REM sleep. The Swiss study's new results were published in the journal Current Biology.
In that journal paper, the researchers rather remarkably explained, “The aim of exploring the influence of different lunar phases on sleep regulation was never a priori [sic] hypothesized. We just thought of it after a drink in a local bar one evening at full moon.”
That interesting admission led researchers from the University of Gothenburg's Sahlgrenska Academy to build on the original work reported last year. It must be pointed out that, with the Swiss exception, many studies have previously been undertaken with the goal of either proving or disproving any correlation between sleep and the lunar cycle. One large study at the Max Planck Institute analyzed data from more than 1,000 people over 26,000 nights of sleep, only to arrive at the conclusion that there was no correlation.
This is where Michael Smith and his fellow researchers at Gothenburg step in. The team analyzed data collected in a previous study that focused on a cohort of 47 healthy 18- to 30-year-olds. Their findings, published also in the journal Current Biology, support the theory that a correlation between the lunar cycle and sleep patterns does, in fact, exist. Their paper is entitled 'Human sleep and cortical reactivity are influenced by lunar phase.'
“Our study generated findings similar to the Swiss project,” Smith says. “Subjects slept an average of 20 minutes less and had more trouble falling asleep during the full moon phase. However, the greatest impact on REM sleep appeared to be during the new moon.”
Much like the Swiss study, Smith and his team began their study looking not at the moon but in a completely different direction. “The purpose of our original study was to examine the way that noise disturbs sleep,” Smith noted. “Re-analysis of our data showed that sensitivity, measured as reactivity of the cerebral cortex, is greatest during the full moon.”
As their findings explain, greater cortical reactivity was found in both men and women. However, only men had a discernible amount of trouble falling asleep when the moon was full. Additionally, men slept less than the women studied. Skeptics in the scientific community are quick to note that the study might be wrought with error due to issues of both age and gender differences. They also highlight more subtle factors like the physical condition of the individual participants and exposure to light during the day may also be variables that were not properly accounted for.
Fully aware of the points made by skeptics in the community, Smith believes the results of his study should be considered for more intensive future study.
“The rooms in our sleep laboratories do not have any windows,” he explains. “So the effect we found cannot be attributable to increased nocturnal light during full moon. Thus, there may be a built-in biological clock that is affected by the moon, similar to the one that regulates the circadian rhythm.”
“But all this is mere speculation – additionally, more highly controlled studies that target these mechanisms are needed before more definitive conclusions can be drawn,” Smith concludes.
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