On the one hand, there are many legends and esoteric texts about the influence of the moon on the physical and mental state of people, on the other hand, it is lunar rhythms that have become one of the most studied issues in modern chronobiology, and a number of "obvious" lunar influences have not found direct confirmation in experiments. Let's consider the facts in more detail.
HOW THE LUNAR RHYTHMS ARE STRUCTURED
The monthly lunar cycle consists of ≈29.5 days, during which our satellite moves around the Earth, and the daily cycle consists of 24.8 hours (the time from sunrise to sunset). It must be remembered that the duration of the first lunar day can vary, and sometimes it is very short.
Depending on the phase of the moon, the degree of illumination of the night sky also changes, which can also affect a number of processes in nature (for example, the ability to hide from a predator or, conversely, successfully hunt). On a full moon, the illumination of the sky is approximately 25 times higher than during the quarter phases and 250 times higher than on a new moon.
The influence of the lunar rhythms (diurnal and monthly) is a long-standing object of research in marine biology, since in many animals reproductive processes are regulated in accordance with these changes. However, the lunar schedule and the illumination of the night sky can somehow affect land creatures.
LUNAR CYCLE AND STROKE
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Among the most recent and interesting studies about humans is the incidence of different types of stroke in different phases of the moon. Based on the Royal Melbourne Hospital database for 2004-2011, scientists were able to draw several conclusions. It turned out that hemorrhagic strokes are statistically more common in the first quarter of the lunar cycle than in the new moon. Transient ischemic attacks also occurred more frequently during the first quarter and full moon. But the frequency of ischemic strokes was not influenced by the phases of the moon. The study also shows that strokes in general are less common from midnight to 6 a.m. than during the rest of the day.
MOON PHASES AND SLEEP QUALITY
How does a person's sleep quality change depending on the phase of the moon? This important issue is discussed in a large-scale study by specialists from the Center for Chronobiology at the Psychiatric Hospital at the University of Basel.
The scientists evaluated the quality of sleep using an electroencephalograph and did additional tests to compare the subjects' melatonin and cortisol levels. It was found that during the full moon, the deep sleep phase is shortened by 30%, the time to fall asleep is lengthened by 5 minutes, and the total sleep time is reduced by 20 minutes. Interestingly, this work has generated a lot of discussion and criticism on the methods and design of the experiment. More detailed comments can be read here, and another article discussing this work is here. Scientists agree that the complexity of an adequate experimental design to isolate specific connections between sleep patterns and the lunar phase requires more data. And although there is a lot of work in this direction, the question can be considered open.
THE LUNAR CYCLE AND HUMAN PHYSICAL ACTIVITY
The influence of the lunar cycle on human physical activity has not been confirmed. In a recent multinational study, it was shown that physical activity has its own rhythm, but it is not directly related to the moon.
In general, the influence of the movement of the moon on living organisms is described in detail in a number of chapters in the book Circannual Rhythms, and an interesting analysis of the statistically unconfirmed connections between processes in the human body, mental aspects and phases of the moon is given here. Obviously, there are prerequisites for the presence of connections between physiological processes and lunar rhythms, however, the complexity of competently setting up an experiment with the participation of people and the presence of a number of additional influencing factors prevent unambiguous conclusions and formulation of recommendations based on statistically reliable data. We are waiting for new large-scale works from chronobiologists!
