The moon and your health

It influences life on earth but can it affect your physical and mental health?

HEALTH | MARIA COHUT | The moon has held the human mind in its thrall since the dawn of time. Throughout the ages, peoples across the world have worshipped it as an important deity, believing it held real power to influence their lives — and their health. But is this really true

“The moon had been observing the earth close-up longer than anyone. It must have witnessed all of the phenomena occurring — and all of the acts carried out — on this earth,” writes Haruki Murakami in 1Q84.

The earth’s natural satellite has always fascinated human minds. Throughout the ages, humans have worshipped the moon, studied it, and referred to it to predict the direction of their lives… and their state of health.

This fascination with the moon is ongoing. This year, we celebrated the 50th anniversary of Apollo 11’s moon landing, and NASA are making plans to send another human crew to the moon in 2024.

The moon influences life on Earth and natural mechanisms in a way that must have seemed natural hundreds and thousands of years ago. At full moon, corals release eggs and gametes in a reproductive frenzy.

And the gravitational attraction between the moon and the Earth causes sea tides — the rising and falling of the sea.

Since the moon influences such mechanisms of life on Earth, people have also believed that it can affect various aspects of physical and mental health.

But is this true, and to what extent?

The moon and menstrual cycles

Some people still refer to menstrual cycles as “moon cycles,” and many remain convinced that there is a form of synchronicity between the phases of the moon and female menses.

A myriad of webpages and smartphone apps purport to help you track your moon cycle or to achieve full synchronisation between your menses and the phases of the moon.

Some even advise readers on how to maximize their chances of becoming pregnant by taking moon phases into account. But is it true that the phase of the moon can influence fertility windows? This question is far from settled.

The notion that the menstrual cycle and the phases of the moon are somehow linked derives from the concept that, on average, a menstrual cycle lasts 28 days, which is about as long as a moon cycle. The moon takes 27 days, 7 hours, and 43 minutes to complete one revolution around the Earth, and 29.5 days for a moon phase cycle.

In the ’70s, ’80s, and ’90s, various small-scale studies suggested that females’ periods and ovulation phases coincided with the “light” phase (in the leading to full moon), and the “dark” phase (in the leading to new moon) of the moon cycle, respectively.

Some of these studies also found correlations between moon phases, changes in the levels of melatonin — a hormone that helps regulate sleep-wake cycles — and the phase of the menstrual cycle.

As recently as 2005, one study working with a small cohort from Nepal, indicated that women whose ovulation phase coincided with the full moon, and who got pregnant during the full moon, were more likely to give birth to male babies. Those who conceived before the full moon were more likely to give birth to female babies.

However, most periods are unlikely to “synch” with particular moon phases, except by coincidence. Menstrual cycles can last anywhere between 21–35 days, and their length can also change with age and due to hormonal factors.

A more recent 1-year-long retrospective study of 74 females of reproductive age contradicted the idea that the moon had a say in menstrual cycles. The study found no correlation whatsoever between menses, fertility, and the phases of the moon.