A full moon can mess with your sleep

Teresa Tanoos's picture
Study finds sleep disturbed during full moon
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A full moon has been linked to everything from increased crime rates and violence, to heightened anger and even psychosis – and while most of these old wives tales have proven false, a new study has found that a full moon really does mess up your sleep.

The study’s lead author, biologist Christian Cajochen of the Psychiatric Hospital of the University of Basel in Switzerland, reports that he was sitting outside a pub one night with colleagues and gazing at the full moon when a question came to mind: Does the full moon influence sleep?

A discussion with his colleagues then followed, which is when Cajochen, who previously conducted sleep studies, realized that data from such studies might help him determine if the lunar cycle does, in fact, affect sleep.

“It took me more than four years until I decided to publish the results, because I did not believe it myself,” stated Cajochen.

"If you ask people, at least in Switzerland, about 40 percent report feeling the moon during sleep, or they blame the full moon for bad sleep," Cajochen added.

In order to find out if there was a link between sleep and the moon, Cajochen examined the results of a 2000 to 2003 study on circadian rhythms and the sleep-wake cycle. The study included 33 healthy volunteers, between ages 20 and 74, who slept under strictly controlled conditions in a laboratory with no windows, so they could not see the moon.

The participants stayed in the laboratory for three and a half days, where humidity and temperature were controlled. This particular study on circadian rhythms and the sleep-wake cycle did not seek to learn anything about lunar cycles and sleep at the time.

The study involved two full nights of sleep, as well as a third night that included either sleep deprivation or sleep satiation. During this time, the researchers took EEG readings and blood samples from the volunteers to record electrical activity in their brains to help them determine how long and how often the sleep subjects were in deep sleep.

Cajochen recently compared the EEG and blood test results with the lunar cycle, which is when he discovered that during a full moon, people actually slept worse than they did during the new moon phase of the lunar cycle.

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According to Cajochen, deep sleep was, on average, 30 percent decreased around the time of a full moon. He also found that it took an average of five minutes longer for the study subjects to fall asleep during a full moon, and they slept 20 minutes less when the moon was full.

They also had a drop in their levels of melatonin, a hormone that regulates the sleep-wake cycle by causing drowsiness and a dip in body temperature.

“I was also surprised to see, that besides sleep, also evening melatonin levels were affected by lunar phase,” Cajochen said.

Although he remains uncertain as to why sleep is more messed up when the moon is full, Cajochen thinks it may be due to a full moon shedding more light, which can interfere with deep sleep and keep people awake.

If Cajochen’s theory is correct, he admits there’s not much one can do about poorer sleep during a full moon. On the flip side, at least those who have problem sleep during a full moon can rest easier knowing it’s not all in their head.

“If somebody thinks he or she is sensitive to the moon effects on sleep, [doctors] should probably account for that,” he says.

Cajochen also admits that further research is needed to confirm the findings of his study, and that future research would need to be conducted over a longer period of time – at least 30 days to cover an entire lunar cycle.

Nevertheless, this study at least provides evidence that a full moon can impact sleep.

"We have evidence that the distance to the nearest full-moon phase significantly influences human sleep and evening melatonin levels when measured under strictly controlled laboratory conditions, where factors such as light and personal moon perception can be excluded," the study authors wrote.

If you have problems sleeping at any time during the lunar cycle, click here for some tips and more reasons why a good night's sleep is crucial for good health.

SOURCE: Evidence that the Lunar Cycle Influences Human Sleep, Christian Cajochen, Songül Altanay-Ekici, Mirjam Münch, Sylvia Frey, Vera Knoblauch, Anna Wirz-Justice. Current Biology (July 25, 2013).

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