Trending Science: Unlocking the mysteries of the full moon

Always surrounded by an aura of mystery, the moon and its possible influence over human behaviour has been the object of ancestral fascination and mythical speculation for millennia. Many folktales and superstitions accuse the full moon of not only causing restlessness amongst humans but also as the source of greater physical and mental alterations. But is there some scientific truth behind these long-held beliefs? The jury, it seems, is still out.

A Swiss study conducted in 2013 and published in the journal ‘Current Biology’ seemed to indicate that indeed, a full moon has the capacity to disturb an otherwise normal sleeping pattern. They found evidence of a ‘lunar influence’ in a study of 33 volunteers sleeping in tightly controlled conditions. When the moon was round, the researchers discovered that volunteers took longer to fall asleep and had poorer quality sleep - this was regardless of the fact that they were shut up in a darkened room and couldn’t see the moon.

The volunteers also had a dip in levels of melatonin, linked to natural-body clock cycles. The body produces more melatonin when it is dark and less when it is light. Being exposed to bright lights in the evening or too little light during the day can disrupt the body's normal melatonin cycles (a reason why you shouldn’t look at laptops, mobile phones or tablets late in the evening, as these can also increase melatonin levels).

The study’s participants, who did not know the study’s intent, spent two separate nights under close observation and findings revealed that around the full moon, brain activity related to deep sleep dropped by nearly a third. The volunteers also took five minutes longer to fall asleep and slept for 20 minutes less when the moon was full.

These results led the research team to speculate that the lunar cycle seems to influence human sleep, even when the moon is not seen and an individual is not aware of the current phase of the moon’s monthly cycle. Indeed, they raised the possibility that some people may be naturally more sensitive to the lunar cycle than others.

Although the study was greeted at the time by the media and sleep experts as containing significant findings, a more recent study, published in 2016 in the journal ‘Frontiers in Paediatrics’ cast doubt on whether the moon can really have a significant impact on sleep patterns.

This international study, led from the Eastern Ontario Research Institute in Canada, focused on the sleeping patterns of nearly six thousand children from five continents. The children came from a wide range of economic and sociocultural backgrounds. Variables such as age, sex, highest parental education, day of measurement, body mass index score, nocturnal sleep duration, level of physical activity and total sedentary time were considered. The study specifically chose child participants over adults as not only do children require more sleep but are also more sensitive to behavioural changes.

Data collection took place over 28 months, equivalent to the same number of lunar cycles. These were then subdivided into three lunar phases: full moon, half-moon and new moon. The findings obtained in the study revealed that in general, nocturnal sleep duration around the full moon compared to new moon reported an average decrease of five minutes (or a 1 % variant). No other activity behaviours were substantially modified.

Moreover, the researchers explained the 1 % variant through the study’s large sample size that correspondingly maximises statistical power. They also pointed out that a five minute decrease in sleep poses no threat to overall health. Overall, the study concluded that we shouldn’t worry about the full moon having too much of a negative impact on our mental and physical states.

The belief that the full moon has an almost mystical impact on human life will not go away though. Woven into so many of our most cherished myths, legends and folk stories, the moon will continue to excite the human imagination... And will most likely spur further scientific enquiries attempting to debunk once and for all whether or not we are truly affected by the celestial lunar cycle.