Loud neighbors may not be the only thing disturbing people's sleep; new research suggests a full moon could interfere with slumber.
A research team concluded a "lunar influence" affected the sleep of 33 study participants sleeping in "tightly controlled laboratory conditions," the BBC reported.
A full moon kept the participants up, even though they were in a dark room and sheltered from the moonlight.
The researchers also observed a drop in melatonin, a chemical responsible for "natural-body clock cycles." The body has been known to produce more of the chemical when in dark conditions.
Melatonin levels can be affected by being in a very bright area too close to bedtime, or vice versa. These new findings suggest the moon-correlated sleep disruptions don't have to do with light at all.
The participants spent two nights sleeping in the dark room, with no exposure to the moon's light. They were not aware of the study's purpose.
When there was a full moon the volunteer's sleep-related brain activity dropped a third from the night with a milder moon.
"The lunar cycle seems to influence human sleep, even when one does not 'see' the Moon and is not aware of the actual moon phase," Professor Christian Cajochen of the Basel University, said.
The study had not originally set out to study the effects of a full moon on sleep patterns, but the researchers noticed the correlation when reviewing past data.
"There is a such a strong cultural story around the full Moon that it would not be surprising if it has an effect. It's one of these folk things that you would suspect has a germ of truth," U.K. sleep expert Dr. Neil Stanley, said. "It's up to science now to find out what's the cause of why we might sleep differently when there's a full Moon."
