The lunar calendar has long been associated with women’s menstrual cycles, but a new study has officially revealed that the two are intrinsically linked.
Researchers from France and the United States analyzed menstrual cycle data from 3,296 European women and 721 North American women, and looked at whether the dates coincided with specific lunar cycles.
The team found that women in North America often started their period when there was a full moon and European women during a waxing moon.
The researchers believe the timing may be due to their new findings that the measurement is governed by a woman’s internal clock, which can be affected by the lunar cycle.
Researchers have found that the moon plays a role in women’s menstrual cycles because it controls the body’s circadian rhythms, which tells a woman’s body that it is time for her cycle to begin.
The clock controls the daily (or ‘circadian’) rhythm of our body in a 24-hour cycle, which is responsible for waking our body in the morning and ensuring a good night’s rest.
However, it has also been observed that our internal clocks can be affected by the lunar cycle, which can cause people to lose sleep, and a disturbance in circadian rhythms is associated with alterations in menstrual function.
This changes the way our internal clock is calibrated, so “if the cycle lengthens, for whatever reason, this clock-based process adapts to shorten it quickly,” said neuroscientist Claude Gronfier of the University of Lyon. in France. BBC Science Focus.
Researchers discovered that when this happens, it creates something called “phase jumps,” when the biological clock becomes desynchronized due to the waxing moon and attempts to self-correct by advancing to the body’s next stable state.
A phase jump is also known as “relative timing” and occurs in circadian clocks, like the feeling of fatigue and out of sync you get when traveling across time zones.
The researchers analyzed menstrual cycle data from more than 7,000 women on two continents.
The researchers believe the timing may be due to the fact that the measurement is governed by the woman’s internal clock, which can be affected by the lunar cycle.
In some species, measurement can occur twice per lunar cycle when the races are strongest, when the Sun, Earth and Moon are aligned, during the new moon or the full moon.
The team noted that previous research had shown that the menstrual cycles of women with a period longer than 27 days were intermittently synchronized with the lunar cycle.
“Our work confirms and further extends both the oscillatory nature of the menstrual cycle and the possible synchronization in different phases in two larger data sets,” he shares in the study.
They may have developed an internal clock with a period close to that of the lunar cycle at the time they faced the tides.
“So, during the millions of years of hominid evolution, this rhythm may have been active, possibly associated with the lunar nightlight cycle,” the study reads.
“This may have allowed relative synchronization of the cycles of women living together.”
“We have a lot of work ahead of us and we hope that our colleagues will embark with us on what could be a future area of ​​circadian medicine,” Gronfier told the BBC.
“If other studies confirm the existence of an internal clock that controls the menstrual cycle, medical treatment of ovulation disorders could use chronobiological methods that have been shown to be effective in the treatment of cancer, circadian and sleep disorders, and depression. “said the study.
The perceived link between lunar and menstrual cycles has continued through the centuries, dating back to ancient Greek culture, where the word “menstruation” is derived from the Latin and Greek word for moon: mene.
Ancient Greek doctors believed that women were most powerful mentally and spiritually during their menstrual period because it typically occurred during the full moon.
Likewise, in indigenous cultures, the period is known as ‘moon time’, where women still rest at home and reflect on their experiences.
“Women have great power during their moons,” Patty Smith of the Leech Lake Band of Minnesota Ojibwe told Rewire News Group in 2019.
‘As they bleed, they let go of the accumulated experience and stress of being a woman.
“Some of those experiences are painful or may contain negative energy, so we want to be careful not to disrupt that process,” Smith continued.