A new study finds that we sleep less on full moon nights, but researchers do not understand why it happens. The researchers looked for people living without access, or with limited access to artificial lighting, to find the same changes in sleep as the lunar cycle progresses.
Experts are still trying to understand why these sleep changes can happen. We’ve all heard stories about how things can get a little weird during the full moon, from high rates of psychiatric hospitalization to a higher risk of being bitten by an animal.
However, the findings of a study published on Wednesday, January 27, suggest that the full moon affects the way you sleep. The researchers looked at groups with different access to artificial light.
Using wrist monitors, the researchers tracked sleep patterns among 98 people living in three indigenous communities in Argentina. They had different access to electricity during the study period:
-A community had no electricity;
-Another had limited access to electricity, such as a single artificial light source;
-A third community lived in an urban setting with full access to electricity;
The researchers collected sleep data for one to two cycles of the month, for about 75% of participants.
They found that participants from all three communities showed the same changes in their sleep pattern as the moon progressed in its 29.5-day cycle.
Then, they analyzed sleep monitoring data from 464 students from Seattle, collected for a separate study, to find the same pattern of sleep changes.
The sleep was the shortest before a full moon
Although the researchers hypothesized that sleep would be inhibited during full moon nights, they were particularly surprised by two findings.
First, no maximum sleep inhibition was observed exactly on full moon nights, as initially predicted; instead, night activity was increased and sleep was shortest starting with a few nights before the night of the full moon.
The research team, initially believed that this thing was due to the fact that more moonlight is available in the first half of the night, but not necessarily to the nights following the full moon (because the moon rises later each night).
Secondly, they were extremely surprised to find that the effect, although smaller, was present regardless of access to electricity.
It’s all about light
The idea generally accepted by research in the field is that people are really sensitive to light.
We all have a circadian rhythm, a built-in clock, which does not necessarily run a 24-hour cycle and probably runs slower in most people – a 25-hour cycle.
The researchers looked at people living without limited, limited and complete access to artificial lighting to find the same changes in sleep as the lunar cycle progresses. The main limitation of the study is that it cannot establish a causal link between the phase of the moon and the changes in sleep hours.
Obviously, sleep is synchronized with the phases of the moon, but we still don’t know how it happens, according to researchers.