Lunar cycle may have a big impact on men's sleep quality

The waxing and waning of the Moon may have a bigger impact on men than women, at least when it comes to sleep quality. That's according to a new study from Uppsala University, which published the research in the peer-reviewed journal Science of the Total Environment. Unlike past research on the topic, this study accounted for influencing factors like sleep apnea.

The study involved 360 men and 492 women; the research involved recording the participants at night during sleep. Using that data, the researchers linked the first half of the lunar cycle (waxing moon) with poorer sleep quality in men, but little differences in women.

The waxing moon is part of the lunar cycle during which the Moon appears to get brighter and become more full; the waning cycle, meanwhile, is when the Moon appears to get dimmer as the amount of sunlight reflected decreases. It's possible the amount of sunlight reflected by the Moon during the waxing cycle may drive the sleep disturbances observed in male participants.

Unlike past studies on this topic, the researchers with Uppsala University say they adjusted their results to account for possible influencing factors like obstructive sleep apnea and other chronic sleep difficulties.

The study's corresponding author Christian Benedict did note, however, that the researchers "cannot disentangle whether the association of sleep with the lunar cycle was causal or just correlative." Assuming light reflected by a fuller Moon is the driving factor behind the disruption, making sure curtains are closed at night and wearing a sleep mask may help individuals who experience this problem.