National Post (National Edition)
BOO MOON
IT'S NOT JUST THE PANDEMIC. THAT BEGUILING CELESTIAL ORB MAY BE MESSING WITH PEOPLE'S SLEEP PATTERNS, TOO
Sleep and circadian rhythms have long been associated with the powerful effects of the sun cycle. But a growing number of studies have suggested that another familiar celestial body might also be impacting your ability to get a restful night's sleep: the moon.
A paper published in the journal Science Advances found people tend to have a harder time sleeping in the days leading up to a full moon.
Researchers reported that sleep patterns among the study's 98 participants appeared to fluctuate over the 29 1/2-day lunar cycle, with the latest bedtimes and least amount of rest occurring on nights three to five days before the moon reaches its brightest phase. They found a similar pattern in sleep data from another group of more than 460 people.
Ahead of the full moon, it took people, on average, 30 minutes longer to fall asleep and they slept for 50 minutes less, said Leandro Casiraghi, the study's lead author and a post-doctoral researcher in the Department of Biology at the University of Washington.
“What we did is we came up with a set of data that shockingly proves that this is real, that there's an actual effect of the moon on our sleep,” Casiraghi said.
The study involved analyzing the sleep patterns of three Toba Indigenous communities, also known as the Qom people, in northeast Argentina: one rural with no electricity access, a second with limited access and a third located in an urban setting with full access.
Horacio de la Iglesia, one of the study's co-authors and a professor of biology at the University of Washington, said the communities were “ideal” to study because “they are all ethnically and socio-culturally homogeneous, so it has become an outstanding opportunity to address questions about sleep under different levels of urbanization without other confounding effects.”
Participants were outfitted with wrist monitors and information was gathered over one to two lunar cycles.
The data revealed the unusual pattern of decreased sleep quality on nights leading up to a full moon, upending their expectation it would occur the night of the full moon, a trend observed across the three groups.
“When you find what you expected, typically you say, `Well, is this really true?'” he said.
“But when you find something that you did not expect, then you say, `Well, this is a real phenomenon.'”
The surprises kept coming, Casiraghi said.
The scientists also evaluated sleep data from 464 Seattle-area college students.
“The moment I was, like, just completely in awe was when we (looked) at the data from the students,” Casiraghi said. “This beautiful lunar rhythm emerged with the exact same shape and phase as our Toba-Qom subjects ...”
What the data didn't show, though, was a clear answer to a critical question:
Why does this happen?
“The main limitation is that we cannot establish causality,” de la Iglesia said. “We have no idea how the moon is doing this to us.”
One suggestion is that the availability of moonlight changes as the lunar cycle progresses.
“It turns out that the nights that precede the full moon are the nights that have more moonlight availability on the first half of the night,” de la Iglesia said.
The waxing moon not only becomes brighter as it gets closer to a full moon, it also typically rises in the late afternoon or early evening, potentially exposing people to more light. “So if you are awake, you will be kept awake by this availability of moonlight during the evening.”
But that theory might not work as well when applied to people living in urban environments who are exposed to artificial light at night, which is often more intense than moonlight, said Mark Wu, a professor of neurology, medicine and neuroscience at Johns Hopkins University who did not work on the study.
“If there's no light at all, then (moonlight) can be meaningful,” he said. “But with modern lighting, it's essentially irrelevant.”
The findings from the urban populations prompted researchers to include an “underlying hypothesis” in the paper, suggesting that the sleep pattern might be linked to changes in the moon's gravitational pull.
It's possible, de la Iglesia said, that gravitational pull from the moon might make people more sensitive to the availability of light in the evening, whether it's artificial or natural moonlight.
Casiraghi said the researchers plan to “pursue these avenues on these questions, trying to figure out what's the force driving these changes.”
Still, de la Iglesia said the study's findings suggest that the moon's effect on sleep is “so robust that even if we don't know the mechanism, we can still capitalize on the finding.”
For people who suffer from insomnia, it could help you figure out which nights to pay more attention to good sleep hygiene.
Sleep experts often recommend reducing exposure to light at night, especially blue light, which arouses the brain, causing delays in sleep onset, and can shorten sleep.
Casiraghi said the study's findings may serve as a reminder of nature's power.
There is already good evidence that trying to “fight against environmental cycles and trying to counterpoise your will to sleep at a different time against the natural cues is actually very bad for your health. We now have more evidence that you can't just get rid of environmental cues.”
WHAT WE DID IS WE CAME UP WITH A SET OF DATA THAT SHOCKINGLY PROVES THAT THIS IS REAL, THAT THERE'S AN ACTUAL EFFECT OF THE MOON ON OUR SLEEP.