Sleep Tied to Phases of the Moon? According to this Swiss study, it seems that during the full moon NREM deep sleep decreases by 30%;  it takes 5 minutes longer, on average, to fall asleep; and melatonin production drops.  All this leads to a subjective decrease in sleep quality.

Christian Cojochen, professor of neuroscience who headed the study at the University of Basel was puzzled saying “The only explanation we could come up with is that maybe there is a lunar clock in the brain, as found in other species like fish and other marine animals, but we don’t have direct evidence for that.”