The placement of the moon in the sky might not even cross your mind when it comes to improving your sleep hygiene, but the phases of the lunar cycle can have an effect on your sleep. Here is what the science says about how the moon affects sleep and how you can get quality sleep regardless of the moon’s phases.
Does the moon affect sleep?
The idea that the moon affects human behavior dates back centuries. The ancient Greek physician, Hippocrates, believed the moon could induce madness in some people and stories of werewolves — people who turn into wolves during a full moon — are a popular part of folklore across many different cultures.
Today, tales that a full moon causes pregnant women to go into labor, induces seizures or increases the rate of psychiatric hospitalizations continue to keep mythical narratives about the moon alive. Many of these claims are mostly urban legend with little scientific backing, but there is some research to support the idea that the moon can affect sleep. And disrupted sleep does impact human behavior.
A 2013 study found subjects took five minutes longer to fall asleep, slept for 20 minutes less and spent 30% less time in deep sleep during a full moon, though a follow-up study did not replicate findings.
A 2021 study published in Science Advances tracked people living in three different communities in Argentina, all with different levels of access to electricity, and found the same sleep patterns across participants in each community — on average, people went to bed latest and slept the least three to five days before a full moon. This was true for those with or without electricity and sources of artificial light.
More research is needed to draw conclusions about how the moon affects sleep, but so far the science appears to indicate a correlation.
Why the moon affects sleep
Scientists are still unsure of the exact mechanisms for how and why the moon may affect sleep, but the brightness of the full moon is thought to play a role, says Alex Dimitriu, MD, Founder of Menlo Park Psychiatry and Sleep Medicine.
Humans are very sensitive to light and our exposure to light can have a significant impact on our circadian rhythm — the internal body clock that helps regulate sleep and wake cycles. Darkness stimulates the production of a hormone called melatonin, which helps us sleep, while exposure to light in the evening has been shown to inhibit melatonin production.
Artificial light from lamps and screens in our homes seems to have the biggest impact on melatonin production, but light from the moon can also affect circadian rhythm, Dimitru says. The moon becomes brighter in the nights leading up to a full moon, which could explain why study participants in Argentina slept the least three to five days before a full moon.
“The moon, by providing brighter light in the evening may indeed entrain our circadian rhythms,” Dimitriu says. “ Likely this takes time, being outdoors and without interference from artificial light sources. A single glance at a full moon on one night, may not be enough to alter sleep immediately.”
Another possible explanation is the moon’s gravitational pull, though more research is needed to study this link, Dimitriu says. In the Argentina study, participants slept less in the days leading up to the full moon, regardless of their exposure to artificial light, which “raises the possibility that the moon’s gravity could have a time-of-day specific effect on sleep,” the researchers say.
“As expected, the effect of the moon is diminished as more artificial light is present, but per this study an effect for moon phase persists,” Dimitriu says. “Can gravity affect melatonin or some other circadian modulator? Possibly. But we’d need that data to be sure.”
How to improve your sleep regardless of the lunar cycle
The moon may affect sleep in ways scientists are still trying to figure out, but exposure to light in your home is likely to have a bigger impact, Dimitru says. There is little you can do to influence the moon or change how it may affect your sleep, but there are steps you can take to improve your sleep hygiene and get quality sleep, regardless of how bright the moon is in the sky.
Establish regular sleep and wake times. This will help reinforce your natural sleep-wake cycle.
Minimize your exposure to artificial light by dimming lamps in the evening and turn screens off at least half an hour before bed.
Avoid spending time outside in the evening when the moon is at its brightest. Shut blinds in your bedroom and invest in blackout curtains if moonlight comes into your room.
Exercise daily. Physical activity is not only good for your overall health, but can also help you feel more tired and ready for sleep at night.
For centuries, people have created stories about the moon’s mysterious impact on humans. And as scientists continue to explore this link, you can take steps to improve your sleep quality and reduce the moon’s effect on your sleep.