The Sun, The Moon, and Me: Circadian and Infradian Rhythms
This post will explore the relationship between your hormonal rhythms and the earthly rhythms of the solar and lunar cycle. Our bodies natural rhythms are intimately tied in with the larger rhythms of this planet. The systematic denial of this fact has negative impacts on our body, mind, and spirit.
Circadian comes from Latin - circa (around) + diem (day) = the solar cycle of 24 hours or one day
Infradian comes from English - infra (below) + circadian (single day) = cycles that have a period of recurrence longer than one day, in other words, the menstrual cycle.
Menstrual comes from Latin - mēnstruus (month/monthly) - and other related root words like mensis/mehns (moon) as well as meh (to measure) referring to the moon phases as a measure of time.
It's clear through language, culture, and ritual, that ancient people were aware of the fact that the human body, and specifically the menstrual cycle, were intertwined with the lunar and solar rhythms. Sadly, because we live in a patriarchal system today, only the solar cycle is really studied and understood. A great deal of research has gone into studying the circadian rhythm and how it works.
But there's been much less research studying the infradian rhythm by contrast. For those of us in our menstruating years, we exist on two levels at the same time. This makes our hormonal system particularly complex and we are deeply affected when either the circadian or infradian rhythm is disturbed. To make things even more complex, one rhythm affects the other. Our ovulatory cycles affect the circadian rhythm and vice versa. Dysregulation of one cycle usually means some kind of disruption to the other.
The Circadian Rhythm
24 hour lifelong clock
regulates digestion, body temperature, metabolism, sleep, elimination, hormone production
Melatonin and cortisol are reliable markers of the circadian phases
Melatonin secretion begins around 9pm to induce sleep
Cortisol secretion begins around 6am to begin the waking day
Both hormones are sensitive to environmental factors like retinal light exposure (which suppresses melatonin secretion) and stress (which stimulates cortisol release)
The circadian rhythm follows the rhythm of the sun and may shift with the changing seasons and geographical location
The Infradian Rhythm
The infradian, menstrual cycle rhythm begins in puberty.
Menarche, your first menstrual cycle, is the beginning of your infradian rhythm, and it ends at menopause, one year after your final menstruation.
There are four phases to your infradian rhythm - follicular (7-10 days), ovulatory (3-4 days), luteal (10-14 days), menstrual (3-7 days) with a variety of hormonal changes throughout
Influences your body, mind, and spirit, giving you different advantages at different phases
We are closely following the infradian rhythm when we use the symptothermal method of fertility awareness. We can use many signs from our body to understand and roughly measure our hormone levels and when ovulation occurs. This sets us up for success because we can use the cycle to our advantage to make life easier and our quality of life better.
The infradian rhythm as expressed through the global average menstrual cycle length is 29.3 days, which is the length of one new moon to the next new moon (29.5) days.
Although our cycle does not always align perfectly with the moon phases, you can help your body do this by opening your curtains at night and eliminating all other light sources in your room.
It's likely that if people were being studied before the intervention of artificial light and technology, that their cycles more commonly synced with the lunar cycle and therefore, with one another. The history of menstruation is deeply communal and probably connected to the lunar cycle in ways that are not revealed to us in modernity. Many cultures have folkloric and ritualistic ties to the lunar cycle.
How does one clock affect the other?
Disturbances to your circadian rhythm can and do affect your menstrual cycle. This is why, in fertility awareness, we do not *predict* ovulation. One of the major factors that can make the fertile window and ovulation fluctuate, is how well the circadian rhythm is doing. If ovulation is delayed, you lose the balance between the menstrual hormones estrogen and progesterone. That further dysregulates both the infradian rhythm (menstrual cycle) and the circadian rhythm.
On average, women experience insomnia more frequently than men. Menstrual cycle changes in reproductive hormones and their interaction with circadian rhythms contribute to sleep issues, as discussed in detail above. Circadian and menstrual processes interact in the regulation of REM sleep.
The menstrual cycle, or infradian rhythm, relies on a balance between estrogen and progesterone in the differing phases of the cycle. The same is true on a faster cycle for the daily rhythm with melatonin and cortisol. Change is a part of the system, and the body is not supposed to be static, but rather flowing in balance.
How to Align Both of Your Rhythms
Becoming more aware of both circadian and infradian rhythms and how they function is vital to the alignment of our physical, hormonal, mental, and spiritual health.
Some reproductive and overall health issues have clear correlation to circadian issues, like PCOS, fibroids, endometriosis, thyroid problems, autoimmune diseases, depression, and more.
Optimizing your circadian and infradian rhythm will help you take advantage of your time and have a higher quality of life. Once you start to understand these rhythms, it becomes easier to see how much they actually affect you, and you'll stop fighting yourself so much.
Draw harder boundaries in regards to your time and which phases of the cycle you feel like expending energy onto others. Prioritize the time where you feel yourself wanting to be focusing inward.