Are you sleeping badly? The moon might have something to do

Sleep problems can have multiple causes, manifest in a variety of ways, and occur sporadically or chronically. But in this multifactorial origin Can the moon play a role?

A recent study published in the journal Science of the Total Environment adds new findings to a controversial topic: whether human sleep is influenced by the lunar cycle.

Previous work has produced somewhat contradictory results on the association between the Lunar cycle of 29.53 days and the dream: some reported an association while others did not.

Among the surveys that have tried to shed light on the issue, there is one that has had local participation. Using wrist accelerometry in two cohorts from Argentina and one from the United States, with a total of 562 participants, the researchers reported an hour of falling asleep later and a shorter sleep time between 3 and 5 days before the night of the full moon.

Other studies carried out in Sweden, Switzerland and Tunisia have reached similar conclusions (more difficulty falling asleep and less duration). But three other large samples attempted to replicate the effects of the lunar cycle on human sleep. they missed.

There are several possible explanations for these divergent results, such as the fact that some of the results were chance finds.

Additionally, many previous studies examining the association of the lunar cycle with human sleep did not control their analyzes of confounding factors known to affect human sleep, such as obstructive sleep apnea and insomnia.

This was warned by scientists at the University of Uppsala, Sweden, who faced what they claim to be the largest study to date who studied the association of the lunar cycle with sleep (evaluated by polysomnography) in 800 men and women and in a large age group (22 to 81 years).

The lunar cycle

“Our polysomnography study in a Swedish community suggests that the lunar cycle can affect sleep in humans, with more pronounced sleep disorders in men than in women, ”concluded the team led by Christian Benedict, associate professor in the department of neurosciences at Uppsala University and head of the study.

During the growth period, the amount of illuminated lunar surface seen from Earth increases, and the time when the moon crosses the meridian gradually changes to late at night. On the contrary, during the waning period, the illuminated area decreases, and the time when the moon crosses the meridian gradually changes to the hours of the day.

To assess the potential influence of this cycle on people, the researchers used the sleep records of 492 women and 360 men.

“We found that men whose sleep was recorded during the nights of the increasing period of the lunar cycle had a reduced sleep efficiency and longer waking time from the onset of sleep compared to those studied during the nights of the waning period, ”said Benoît.

And he added: “On the contrary, women’s sleep was not affected largely by the lunar cycle. Our results were robust to adjustment for chronic sleep problems and severity of obstructive sleep apnea. “

Question of light?

One mechanism by which the moon can affect sleep is sunlight reflected by the moon around the times when people usually go to bed. In addition, a recent study suggests that the male brain may react more to ambient light than that of women.

Since this was an observational study, the research cannot prove cause and effect. In other words, “it is impossible to determine whether the association of sleep with the lunar cycle was causal or simply correlative,” concluded Benedict.