Research Suggests the Moon May Affect Us More than Scientists Thought
Science admits there may be some truth to ancient beliefs about the Moon's influence over us
Hiya!
Even though I struggle to stay up late, I love the night — the stillness, the magic, the stars, the moonlight. The Moon is said to have great powers, that its very presence can alter our bodies and minds. The word lunatic, or lunacy, derives from the Latin word for moon because people thought the Moon made us more erratic and violent.
However, scientists have denied such beliefs about the Moon’s influence over us, saying that humans are immune from any of its possible effects. Yet, recent research is challenging this stance. Now, studies suggest the lunar cycle can influence our sleep patterns and the periodic mood swings of people with bipolar disorder.
Lunar Influence
With its enchanting eight-phase light show and the fact that we only ever see one face of it, the Moon has always enamored Humans. Our shared history is full of numerous stories, myths, and legends about the Moon and the gods and goddesses created in its name. And, of course, let’s not forget about werewolves, the counterpart of vampires, who turn into ravaged beasts during the full moon when it’s brightest.
But our obsession with the Moon goes well beyond the fanciful. In the 13th century, we blamed the Moon, especially full moons, for various psychiatric conditions.
Our beliefs about the Moon and its influence over us have changed over time as science learned more about it, but our obsession with the Moon hasn’t waned (pun intended), and for good reason. Everything we learn about the Moon only inspires further awe and intrigue.
The moon's eight phases are the result of shadows and the Sun’s light reflecting on its monochrome surface. A Full Moon happens when the side of the Moon facing Earth is fully illuminated by the Sun, whereas a New Moon occurs when the Sun illuminates the side of the moon that faces away from Earth, leaving the side facing Earth in shadows.
We also know we only ever see one side of the moon because of tidal locking and that Earth’s ocean tides are due to the Moon’s gravitational influence. Yet, the Moon influences more than just the tides — it also affects life, especially in the oceans.
Many marine creatures, including bristle worms, corals, crabs, fish, mollusks, and sea urchins, breed around the full moon, and the reproduction cycles of certain marine animals coincide with specific moon phases.
The Moon also influences life on land as it’s vital for birds’ navigation and migration. Even certain plants are nocturnal. For instance, Ephedra foramina, a shrub-like plant found nearly worldwide, produces droplets of pollen in bright moonlight to help attract nocturnal pollinators.
Once the whole lunacy debacle was debunked, researchers dismissed any claims that the Moon influences humans — although that didn’t stop research into the subject. Still, such investigations, including several extensive studies, found no more homicides or admissions to trauma centers or mental health units than usual during or around full moons — all of which reinforces the idea that we are immune to the Moon's influences.
Yet, more recent research casts enough doubt that scientists think it’s worth revisiting.
Moody Moon Swings?
Considering people have thought the Moon drives lunacy since the 13th century, let’s start with a 2017 study led by psychiatrist Thomas Wehr, scientist emeritus of the National Institute of Mental Health in Maryland, and his colleagues.
For a combined 37.5 years, Wehr and his team tracked 17 patients with bipolar disorder who lived in the United States and who typically cycled between depression and mania every few weeks.
Ultimately, the researchers found that many of the patients’ mood swings were synchronized with full and new moons. Wehr told Katarina Zimmer of National Geographic that “there are people who are really reacting to both.”
He told Zimmer he thinks it’s plausible humans can somehow sense changes in gravity or possibly its effects on Earth’s magnetic field. However, which sense we would use for this is a mystery. Still, Wehr says, “There’s a lot of things we don’t know about how biology responds to [physical] forces.”
Or, as I always say, we don’t know how much we don’t know. After all, we didn’t know about proprioception — the sense of knowing your body’s location in space — until the 20th century. How many other senses might we have that we’re currently unaware of? Anyway, the Moon also appears to affect our sleep.
Sleep
Considering we’ve evolved a circadian rhythm that encourages us to sleep when it’s dark, the idea the Moon influences our sleep seems reasonable. Plenty of research has been done on this, but many studies end with conflicting results, mainly due to bias. Still, there are at least a couple of studies that are more convincing.
Study #1
One issue with previous research occurred when participants knew they were being evaluated for lunar influences. However, researchers at the Psychiatric Hospital of the University of Basel, Switzerland, found a way around this for their 2013 study by telling participants the research was for a sleep study but left out the bit about the lunar cycle.
The team discovered that people took about five minutes longer to fall asleep, slept about 20 minutes less, and spent about 30 percent less time deep asleep in the NREM sleep stage during a full moon compared to a new moon. These changes were also reflected in decreased melatonin levels, our sleep hormone.
Study #2
The 2013 study is interesting, but a 2021 study takes it to another level. Horacio de la Iglesia, a sleep researcher at the University of Washington in Seattle, and his colleagues tracked and compared the sleep patterns of two vastly different populations.
One group included 464 undergraduate students at the University of Washington in Seattle, and the other group was comprised of 98 similarly aged members of the Toba, also known as Qom, one of the largest Indigenous communities in rural Argentina. Unlike the university students, many of the Toba do not use electricity and are subjected to significantly less light pollution.
Both groups’ participants were given Actiwatch Spectrum Plus wrist locomotor-activity loggers (fancy watches) to track their sleep patterns. The University students wore them for one to three weeks, and the Toba participants wore them for one to three months.
At the end of the study, the researchers found that the Toba participants went to sleep an average of 40 minutes later and slept less overall during nights leading up to the full moon. But since the full moon's brightness has long been thought to have influenced later bedtimes before artificial lights became the norm, the researchers weren’t very surprised by the results.
What de le Iglesia found “super surprising” was the similar reduction in sleep at the same time for the college students living in Seattle. Like many large cities, Seattle's artificial light drowns out stars and moonlight, and like many urbanites, the student participants often didn’t even know when the full moon was. I mean, I couldn’t tell you when the next full moon is without looking it up.
De le Iglesia told Zimmer he suspects ancient hunter-gatherers evolved a way to sense the lunar cycle. He doesn’t know which sense this might be but thinks it may have made them more alert during full moons, perhaps for social activities or using the bonus light to collect additional resources.
Yet, the team discovered another surprise. Many participants of both groups also slept less in the days leading up to and right after the new moon — when the moon isn’t typically visible. This finding suggests there’s more to the Moon’s possible effects on us than just moonlight.
De la Iglesia figures that if it’s not moonlight, then these observed shifts in sleep patterns may be due to the Moon’s gravitational forces, which are strongest during the full and new moon phases because that’s when the Sun, Moon, and Earth are in alignment.
His hypothesis seems reasonable — after all, light and gravity are the two main effects the moon has on Earth. However, Tessmar-Raible, who is also at the Alfred Wegener Institute for Polar and Marine Research and the University of Oldenburg in Germany, told Zimmer the problem with de le Iglesia’s idea is that, so far, there’s no evidence that animals, including humans, can detect such slight changes in gravity.
Of course, just because we don’t have evidence doesn’t mean we won’t, especially since researchers weren’t looking for this ability in animals before. And besides, if animals can see lightwaves that we can’t or sense Earth’s magnetic field, then it doesn’t seem too far out there to think animals could sense slight changes in gravity too.
Perspective Shift
After decades of dismissing the idea that the Moon could influence us, studies like these are beginning to push back and are encouraging scientists to determine once and for all whether humans are biologically capable of sensing moon-related changes and, if so, how we do it.
Such research would do more than satisfy our curiosity; it would deepen our understanding of human health and biology. Since all the research discussed today indicates that sleep is affected by changes in the Moon and since sleep (good or poor) is repeatedly shown to influence our physical and mental health, it seems worth learning more about.
While more research is needed, I always find it interesting and a bit relieving to hear about research investigating ancient ideas that have remained until modern times.
I mean, I always thought it’s amazing how some knowledge, beliefs, and practices — such as yoga, massage, acupuncture, astrology, tarot, and more — manage to survive the test of time. Many such ideas are mocked or labeled New Age, but I think there’s probably a reason they haven’t disappeared.
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"New Moon occurs when Earth drapes the Moon in its shadow." This is very wrong: New moon occurs when the Earth and the Sun are on opposite sides of the lunar orbit (when the moon is between the Sun and the Earth) and since only the invisible side of the moon is lit there is no reflected sunlight that reaches the Earth's surface. Full moon happens in the opposite configuration (the Earth and the sun are on the same side of the Moon orbit - the Earth is between the Sun and the Moon) and light reflected from the entire lit surface of the Moon reaches the surgace of the Earth .
That is why complete Solar eclipses can happen only during New moon, and complete Lunar eclipses (when the Earth truly "drapes the Moon in its shadow") happen only during Full moon.
Thought provoking and interesting. I don’t doubt that many little-understood fields affect us in many ways. Thanks