For thousands of years, humans have wondered if the moon can ruin a good night’s sleep. The ancient Romans thought bipolar disorder and epilepsy were caused by sleeping in the light of a full moon, and the word “lunatic” originally referred to those afflicted by what was thought to be moon-induced illness. Famously, Medieval Europeans believed that our lone satellite’s light had the power to transform people into werewolves. In more modern times, several experiments on the matter have been contradictory: Some say the full moon aids sleep; others say it prohibits it; still others say it has absolutely no effect.
A recent study examined the moon’s effect on sleep yet again — this time focusing on how its pull might affect kids. Researchers looked at the data of 5812 children with diverse socioeconomic statuses from 12 countries. The data revealed they the kids lost an average of five minutes less shuteye during full moons, a 1 percent change in total sleep time. In other words? That big piece of cheese in the sky doesn’t really see, screw with kids’ sleep habits.
In the ensuring paper cheekily titled, “Are Children Like Werewolves?” the study’s authors write “whether this minimal difference is clinically meaningful is questionable.” (While this might seem like a giant waste of a medical study, the research was conducted to investigate the relationship between sleep and childhood obesity. The moon researchers simply examined the data after it had already been collected.)
Despite their lackluster findings, the team wasn’t sure what exactly caused those five minutes of lost sleep. Children lost the same small amount of shuteye regardless of location, weight, and parental income. The sky is 250 times brighter with a full moon than with no moon, but the prevalence of artificial light and bedroom curtains probably balanced out the extra brightness. The study’s authors hint that the root cause could be a biological cycle linked to the moon, similar to how our 24 hour circadian cycle is based on sunlight. But they don’t know for sure.
In a 2013 study published in “Current Biology” one of the authors posited that early humans might have evolved to sleep more lightly during the full moon, as the bright sky meant predators could find them more easily. The theory has some backing in nature: large carnivores like lions catch less prey on full moon nights, and have to hunt during the day to make up for it.
Although the existence of a human lunar clock needs more research to be taken seriously, the moon has a powerful effect on much of the animal kingdom. Earth’s biggest reproductive event happens seven days after every full moon when more than 130 different types of coral spawn at the same time in the Great Barrier Reef. They fill the water with a huge pink cloud of sperm and eggs that eventually sink to the bottom and grow new formations. The moon also has an amorous effect on the Palolo worms of the Samoan islands, who mate in huge swarms during the last quarter of the moon cycle.
Like all animals, humans evolved sleeping under the moon. The 1 percent loss in sleep might be the less vestige of an ancient influence on our nights that’s gone the way of the saber-tooth tiger. Or maybe we’re all a little werewolf.