Women's Cycles and Light Pollution
HOW WOMEN GOT OUT OF SYNC For centuries, folklore and culture have linked the 29.5-day lunar cycle to the average female menstrual cycle. New research suggests this wasn't just folklore—it was a biological reality. This connection, however, has recently been broken. A 2025 study reveals that modern life, particularly our light environment, has "desynchronized" women from this natural rhythm. Below, we explore why this happened and the simple steps you can take to support your body's internal clocks. WHAT THEY LOOKED AT Researchers, led by chronobiologist Dr. Charlotte Förster, analyzed long-term menstrual records from 22 women, with some data stretching back to 1950. They compared these cycles against the phases of the moon. - They specifically looked at women who were not using hormonal contraceptives. - The goal was to see if menstruation starting dates clustered around specific moon phases (e.g., full moon or new moon). WHAT THIS PROVED: THE 2010 PROBLEM The data showed a stark difference between the past and the present. - Before 2010: A clear pattern existed. Women’s cycles frequently "coupled" with the lunar cycle, with menstruation tending to start around either the new moon or the full moon. Over 90% of women in the study showed this synchrony for at least some period of time. - After 2010: The synchronization "completely disappeared." The data became random, with no clear relationship between the cycles. So, what happened around 2010? The mass adoption of LED screens and smartphones. KEY TAKEAWAYS: HOW PHONES SCRAMBLE YOUR CLOCK