Full moon: Bad sleep in this phase of the moon – all just imagination?

myth check
We sleep badly on a full moon – right?

Didn’t get a wink tonight? The culprit for many people: the full moon. What is true about the belief that the phases of the moon have an impact on the quality of our sleep.

Anyone who wakes up in the morning crumpled up and can hardly open their eyes likes to blame the miserable sleep on the full moon. But do we really sleep worse on a full moon, or is that just a myth?

Researchers have also been dealing with this question for a long time – however, it is answered differently in studies. Some research finds evidence that the phases of the moon may affect our sleep, and others find no evidence for this. Therefore, many scientists assume a subjective effect. For example, the sociologist Edgar Wunder. He has analyzed several hundred studies dealing with the influence of the moon on sleep. He comes to the conclusion: “In my opinion, there are no convincing studies that have shown such a connection,” he told Deutschlandfunk Nova.

Full moon and poor sleep – all just imagination?

Researchers from Washington University studied the sleep behavior of four different groups of participants over two lunar cycles. One group were students from Seattle and the other three groups were made up of indigenous people from Argentina, some of whom live in rural areas with no or limited access to electricity. The scientists equipped the participants with a bracelet that recorded their sleep based on various measured values.

The researchers noticed periodic fluctuations in sleep patterns in all four groups. And this despite the fact that the participants live very differently and not all test subjects are exposed to artificial light. Three to five days before the full moon, people from all four groups fell asleep 30 to 80 minutes later than their normal bedtime. And slept 20 to 90 minutes less overall. There were only minor differences between the indigenous population, who have no access to electricity, and the students from the big city. “We see a clear lunar influence on sleep here,” study author Horacio de la Iglesia told Scinexx.

Possible explanation: evolution and gravity

One possible explanation for the phenomenon: “We suspect that the sleep patterns we observed were beneficial to our ancestors because they were then able to take advantage of the additional evening light from these phases of the moon,” lead study author Leonardo Casiraghi told Scinexx. But anyone who lives in a big city knows that neon signs or the illuminated house number of the neighboring house shine far brighter into the apartment than the moonlight. The scientists therefore have another assumption. They suspect that the moon’s gravitational influence could affect our sleep patterns.

Exactly which factors play a role in sleep in the different phases of the moon was not clearly clarified in this study, and further research is needed. One point of criticism of the study: According to Edgar Wunder, the duration of the study over two lunar cycles (around two months) was too short to be able to rule out pseudo-effects. You would also need to check the days of the week. After all, many people go to bed later at the weekend.

Moon phases and sleep

In 2013, Christian Cajochen and his team from the University of Basel examined the influence of the moon on sleep quality. To do this, the scientists measured the brain waves, eye movements and hormone levels of 33 people in the various sleep phases in the sleep laboratory. The subjects were accommodated in the laboratory without windows and did not know what the phase of the moon was.

The result: when the moon was full, the subjects took an average of five minutes longer to fall asleep. And they also lean a total of 20 minutes less. The scientists also found that activity in the brain regions associated with deep sleep fell by 30 percent.

But there is also criticism of this study: With the small number of test subjects, no conclusions can be transferred from the group to the population. In addition, due to the small number of participants, it cannot be ruled out that the results discovered were only found by chance. This needs to be investigated in a larger study.

In contrast to the other two studies, a study by the Max Planck Institute found no connection between the phase of the moon and our sleep. The researchers analyzed the sleep data of 1265 subjects over 2097 nights. “We could not show any statistically verifiable connection between human sleep and the phases of the moon,” said Martin Dresler neuroscientist from the Max Planck Institute in a statement on the study.

No clear scientific evidence

For sociologist Edgar Wunder there is a fundamental problem in researching the influence of the moon on sleep. It cannot be ruled out that the bad sleep at full moon is caused by a psychological effect. If you think that you sleep badly on a full moon, you will also sleep badly because you are stressed and this has a negative effect on your night’s sleep. In order to be able to exclude the psychological factor, test subjects would have to be isolated for a long period of time (half a year to a year) and not know what phase of the moon it is in order to be able to examine the influence of the moon on our sleep well. Such a study is of course not feasible for ethical reasons.

In other words, there is no scientific evidence that there is a connection between poor sleep and a full moon. Some studies only provide hints.

Sources: Communication on the study from the Max Planck Institute, Study Washington University,Study at the University of Basel, Communication on the study by the University of Basel, Deutschlandfunk Nova, scinexx

Also read:

– You can’t go swimming on a full stomach, right?

– If you have a cold, you should avoid milk, right?