How the Moon affects the Sea Levels and Human beings.
Menstrual cycles also aligned with the tropical month (the 27.32 days it takes the moon to pass twice through the same point in its orbit) 13.1% of the time in women 35 years and younger and 17.7% of the time in women over 35, suggesting that menstruation is also affected by shifts in the moon’s gravitational pull
Moon Cycles Exert an Influence on Menstruation and Sleep Patterns
28 January 2021
by: Shannon Kelleher
The moon may not drive people mad or trigger werewolf transformations, but lunar cycles do, in fact, appear to affect human biology by influencing menstrual and sleep cycles, according to two studies published in the January 29 issue of Science Advances.
An analysis of sleep cycles in rural and urban indigenous Argentinians as well as urban U.S. university students found that people fall asleep later and sleep less on the nights leading up to a full moon, when moonlight fills the night sky after dusk. The findings suggest that human sleep is synchronized with the moon’s phases regardless of ethnic or cultural differences — and even in locations where light pollution outshines moonlight.
In a related study, an investigation of long-term menstrual cycle records maintained by 22 women shows that women with cycles lasting longer than 27 days intermittently synchronized with moon phase cycles and the moon’s gravitational pull. This synchronized
sy#hroy was lost as women aged and when they were exposed to artificial light at night.
The researchers hypothesized that human reproductive behavior may have been synchronous with the moon during ancient times, but that this changed as modern lifestyles emerged and humans increasingly gained exposure to artificial light at night.
“I was surprised and fascinated at the same time, although our study is not at all the first report of an influence of the lunar cycle on humans and in many marine animals reproduction is strongly coupled to the moon cycles,” said Charlotte Helfrich-Förster, a professor of neurobiology and genetics at the University of Würzburg in Germany. “Nevertheless, most researchers are skeptical about an influence of the moon on human life.”
THAT TIME OF THE (LUNAR) MONTH
While some older research suggests that women with menstrual cycles that most closely match lunar cycles may have the highest likelihood of becoming pregnant, lunar influence on human reproduction remains a controversial subject. Helfrich-Förster admitted she was skeptical when she first noticed women saying that their periods coincided with the full moon — but her skepticism wavered as she received records of menstrual cycle onsets from different women over the course of several years. When she plotted these records in relation to the full moon, Helfrich-Förster found, to her amazement, that the women’s periods did actually occur during the full moon for certain time intervals — but never indefinitely.
“I started to ask more and more women about such recordings,” said Helfrich-Förster.
The scientist and her colleagues gathered menstrual cycle data kept by 22 women spanncover any times during which the women’s menstrual cycles occurred in sync with lunar cycles, the researchers displayed the data as graphs that show time-based relations along with fluctuations in the moon’s cycles.
Unlike previous studies of this phenomenon, which tended to investigate large numbers of women over short periods of time, Helfrich-Förster and colleagues analyzed records from a small number of women over long periods of time.
“I think that many of these studies missed a synchronization to the lunar cycle, because there is a high variability between individual women and because all women respond to the lunar cycle only during a relative short time interval in their life, ranging from few months to several years,” said Helfrich-Förster.
The researchers found that most women’s menstrual cycles aligned with the synodic month (the time it takes for the moon to cycle through all its phases) at certain intervals, with the periods of women age 35 or younger synchronizing with the full or new moon for 23.6% of the recorded time, on average. Women over 35 only showed this synchrony about 9.5% of the time.
Menstrual cycles also aligned with the tropical month (the 27.32 days it takes the moon to pass twice through the same point in its orbit) 13.1% of the time in women 35 years and younger and 17.7% of the time in women over 35, suggesting that menstruation is also affected by shifts in the moon’s gravitational pull. Furthermore, the researchers observed greater synchronization between lunar and menstrual cycles during long winter nights, when women experienced prolonged exposure to moonlight.
“It is hard to say what [these findings] mean for our lives, but in the worst case fertility is to some degree dependent of the moon cycle and suffers from our modern lifestyles in large cities,” said Helfrich-Förster.