Does the Moon Cycle Effect Humans?

There’s certainly lots of anecdotal evidence of the effect of the moon cycles on human behavior… ask any teacher or emergency room nurse if things get a little more loony at the full moon. But do we have any scientific evidence of it?
MoonAt first glance it would seem quite logical that an orbiting body that can have a powerful effect on the waters of the ocean, via the tides, would also have a powerful effect on other earth inhabitants, particularly humans who are composed of approximately 60% water.

Several of the studies done have be debunked or refuted due to statistical errors and such. I have included links to several studies. However, one completed just this month at the University of Basel shows conclusive evidence on the impact of moon cycles on human sleep patterns:

Around the time of the full moon:
– Brain activity related to deep sleep dropped by 30 per cent
– Subjects took five minutes longer than normal to fall asleep
– They slept for 20 minutes less overall
– Study participants felt their sleep was poorer and showed diminished levels of melatonin, a hormone known to regulate sleep and wake cycles

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Aside from this brand new study, most of my other research shows that there are as many studies debunking the effect of the lunar cycles on human behavior and physiology as there are studies proving the effects.

Another interesting abstract does show that there appears to be a correlation between moon phase and stock returns.

The findings indicate that stock returns are lower on the days around a full moon than on the days around a new moon.

The data show that the lunar effect is not explained away by announcements of macroeconomic indicators, nor is it driven by major global shocks. Moreover, the lunar effect is independent of other calendar-related anomalies such as the January effect, the day-of-week effect, the calendar month effect, and the holiday effect (including lunar holidays).

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And then there’s this report from the Journal of Private Equity:

We find strong lunar cycle effects in stock returns. Specifically, returns in the 15 days around new moon dates are about double the returns in the 15 days around full moon dates. This pattern of returns is pervasive; we find it for all major U.S. stock indexes over the last 100 years and for nearly all major stock indexes of 24 other countries over the last 30 years. Taken as a whole, this evidence is consistent with popular beliefs that lunar cycles affect human behavior.

Following is one of the studies that has apparently been debunked by the Skeptic’s Dictionary, but at the time, they stated that there was definitely a correlation in crime activity.

As revealed by correlations of police and fire department data with data from the lunar ephemeris san francisco suicides and florida homicides appear to be directly correlated with the appearance of the full moon. Evidence points to a ‘circa-monthly biological rhythm’ of human aggression that corresponds with the lunar-synodic cycle. By properly applying knowledge of the lunar effect, police and medical personnel can prepare for fluctuations in the rates of crime and psychiatric admissions. References and a lunar ephemeris are provided.

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I happen to believe that we as humans are affected by the cycles of the moon… I think there’s a rhythm to all life and that we are all impacted by the rhythms and cycles of the Universe. It doesn’t matter much to me whether science proves it. But it sure is interesting to see what scientists have found out about these “myths.”



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