January 2025

Cycles

• Cycles Of Life
• The Sun Cycle – Circadian Rhythm
• Metabolic Cycles
• The Moon Cycle – Reproductive Rhythm

Women’s reproductive cycle is about 28 days, the same length as an average month. Many cultures associated the moon with fertility. In modern science, the moon’s influence on human biology has largely been dismissed as a myth, but several studies have linked lunar phases with sleep and mood. As it turns out, it is the sun who has an impact on reproductive hormones.

The Moon Cycle & The Sun

Reproductive hormones

From puberty to menopause, the ovaries produce estrogen, progesterone, and testosterone, while the pituitary gland produces luteinizing hormone (LH).

Reproductive hormones affect far more than just fertility. They impact sleep, mood, metabolic rate, body temperature, glucose metabolism, insulin sensitivity, and more.

Understanding the relationship between reproductive hormones, cortisol, and metabolic hormones is crucial because a balanced endocrine system supports a balanced reproductive system and vice versa.

The three reproductive hormones involved in the menstrual cycle are estrogen, luteinizing hormone, and progesterone.

Estrogen

Estrogen, known as the “women’s hormone,” is mainly produced in the ovaries, brain adipose tissue, stomach, bone, and skin.

In the reproductive system, estrogen is released in a small sac that contains eggs in the ovaries between day one (the first day of your period) and day fourteen. In the context of the menstrual cycle, it is a tissue-building hormone that builds a warm “nest” in the uterus to welcome a fertilized egg.

Estrogen is responsible for the woman’s body’s voluptuous shape, lights the fire in your libido, getting you obsessed with procreation, and also gives you a “high” as it regulates serotonin and increases dopamine secretion, making them calmer and more satisfied.

Estrogen and the circadian cycle interact in a bi-directional way.

In the brain, estrogen can bind to receptors in the hypothalamus involved in melatonin and serotonin production, affecting the timing of hormone production and the awake cycle. Low estrogen is associated with Difficulty falling and staying asleep, earlier morning awakening, reduced deep sleep phases, and low sleep quality.

If you are a woman in pre-menopause or menopause, you might have an AHH moment now. Low estrogen during these times explains why some women toss and turn in their beds as part of their menopausal transition.

Also, estrogen influences daily metabolic rhythm and the regulation of temperature cycles in the brain and all cells in the body. Lower estrogen levels are associated with lower metabolic rate, reduced insulin sensitivity, decreased sensitivity to satiation, and increased fat deposit around the waist.

Again, for those of us in midlife, with less estrogen in the system, it is hard to lose weight from the waistline, and although glucose metabolism was never an issue before, it might become an issue now.

Another hormone affected by estrogen is oxytocin. Estrogen increases oxytocin receptor density in the brain and enhances oxytocin’s effects, making you a loving, trusting, and caring woman.

It might be that lower estrogen levels help women in postmenopause to free themselves from the expectations of others and start putting their needs at the top.

On the other hand, the circadian cycle affects estrogen levels throughout the day, with estrogen peaking in the early morning, gradually declining throughout the day, and being lowest in the evening/night.

Luteinizing hormone (LH).

Luteinizing hormone is secreted by the pituitary gland at the fourteen days of your cycle, initiating ovulation.

Three factors drive ovulation:
Estrogen peak followed by a sharp estrogen drop.
A surge in progesterone
Ovulation is tied to the circadian cycle. Most times than not, ovulation will occur between midnight and six in the morning.

When you think about it, it makes sense that our ancestors were busy hunting for food during the day but had more time to engage in procreation during the dark hours, when they were protected by darkness and hidden in a shelter.

Progesterone

Progesterone is released in the corpus luteum, which is the follicle sac, following the release of the egg in the part of the third phase of your cycle from the 15th day to the 28th.

Progesterone balances estrogen’s drive to build tissue. It thins the walls of the uterus and stimulates blood vessels to supply the endometrium and nutrients to the developing embryo.

Progesterone levels will increase if an egg is fertilized, and the embryo will be nourished throughout pregnancy. If the egg isn’t fertilized, progesterone will drop, initiating meneses.

In addition to balancing estrogen in the reproductive cycle, progesterone plays a role in sleep and metabolism.

Progesterone promotes a good night’s sleep by affecting GABA receptor activity, the timing of sleep onset, and sleep quality and duration. Low levels of progesterone might keep you up at night, while high levels, such as in the luteal phase, might make you feel fatigued.

Progesterone promotes thyroid health and boosts metabolic rate, energy, and vitality. It acts as a diuretic, meaning it helps eliminate excess fluids, reducing blood pressure. In the evening, progesterone reduces basal body temperature in preparation for sleep.

It also has a calming effect on the nervous system, increasing resilience to stress.

Progesterone affects your circadian rhythm by affecting sleep, stress, and metabolism. At the same time, progesterone fluctuates with the sun’s clock. It is highest between six and eight in the morning and gradually declines until it reaches its lowest level in late evening. At night, progesterone levels stay stable.

“As above so below”

The endocrine system is the most complicated system in the body. Although hormones are secreted in minute amounts into the blood, they play a huge role in regulating all the biological processes crucial for survival. At the same time, these minute amounts of hormones connect us to the vastness of the entire universe.

Poets and seers tried to capture the mysterious connection between the singular and the whole. William Blake wrote, “To see a world in a grain of sand,” and the alchemist said, “As above so beyond.”

The logical mind can explain the connection between the inner clocks and cosmic cycles. But the body is one with the cosmos. It is dancing to the celestial music.