According to telegraph: professor Cajochen, said the effect may be a relic of our evolutionary past.
“We didn’t look at the underlying mechanisms, so we have to speculate about why this might be.
On full moon nights there was more light and so in our past the risk of predators was higher, so maybe we needed to wake up more easily.
If you look in the animal kingdom, particularly in marine animals, they still use a lunar clock to synchronise their reproductive behaviour.
In humans I am not so sure we still need it, but you can still see the menstrual cycle of women it is still roughly synchronised to the lunar cycle.
In the past our reproductive cycle may have been linked to this lunar cycle, so perhaps this is biology telling us something.
However, it is hard to see a use for it in our modern lives.”
Our brains are known to respond to the pattern of light and dark known as the circadian rhythm, but links to the lunar cycle have been less well studied.
read more telegraph