People may actually sleep 20 minutes less and take longer to fall asleep on a full moon night, a new study has found.
Numerous studies through the years have attempted to prove or disprove the hypothesis that lunar phases affect human sleep.
Michael Smith and his co-researchers from the Sahlgrenska Academy at Gothenburg University in Sweden have analysed data generated by a previous sleep study and compared them with the lunar cycle.
Based on a study of 47 healthy 18-30 year-olds, the results support the theory that a correlation exists.
"Subjects slept an average of 20 minutes less and had more trouble falling asleep during the full moon phase. However, the greatest impact on REM sleep appeared to be during the new moon," said Smith.
The retrospective study by the Gothenburg researchers suggests that the brain is more susceptible to external disturbances when the moon is full.
"The purpose of our original study was to examine the way that noise disturbs sleep. Re-analysis of our data showed that sensitivity, measured as reactivity of the cerebral cortex, is greatest during the full moon," Smith said.
Greater cortical reactivity was found in both women and men, whereas only men had more trouble falling asleep and slept less when the moon was full.
Skeptics warn that both age and gender differences may be a source of error, not to mention more subtle factors such as physical condition and exposure to light during the day.
"The effect we found cannot be attributable to increased nocturnal light during full moon. Thus, there may be a built-in biological clock that is affected by the moon, similar to the one that regulates the circadian rhythm.
"But all this is mere speculation Ė additionally, more highly controlled studies that target these mechanisms are needed before more definitive conclusions can be drawn," said Smith.
The research was published in the journal Current Biology.