If you turn into a snarling, growling mess every time there's a full moon, rest assured you’re not turning into a werewolf, a new study suggests. It's more likely that you're suffering from a poor night's sleep.

New research from scientists at the University of Basel in Switzerland found that the full moon was associated with a lack of quality shut-eye.

Prof. Christian Cajochen and his team analyzed the sleep of more than 30 volunteers, monitoring their brain patterns, eye movements and hormone secretions as they slept.

They found that the subjects' quality of sleep changed with the lunar cycle. At the time of a full moon:

  • Brain activity in the areas related to sleep dropped by 30 per cent.
  • Subjects took five minutes longer to fall asleep.
  • Overall, subjects slept for 20 fewer minutes.

The subjects also felt less rested during the full moon and had lower levels of melatonin, the hormone that helps regulate the sleep cycle.

"This is the first reliable evidence that lunar rhythm can modulate sleep structure in humans," Cajochen said in a statement.

The findings are published in the journal Current Biology.

Cajochen and colleagues say the lunar cycle’s influence on sleep patterns may be a holdover from centuries past, when the moon's cycles influenced human behaviour, including sleep. While the moon influences behavioural patterns of some animals, including the reproduction habits of marine animals, in modern times electric light may alter the moon’s influence on humans.

The study, Cajochen says, illustrates that the moon still influences the human sleep cycle when measured in a controlled laboratory environment.