It’s 10:20PM. I get ready for bed, but maybe I can slide in one more to-do item before sleeping.
“There, that’s the last email for today.”
I put the laptop away, turn off the lights, and immediately climb into bed.
Fifteen minutes pass. Nothing. Not sleepy.
Last month, we learned about how the reproductive cycle is tightly regulated by constant hormonal communication between the hypothalamus and pituitary gland in the brain and the ovaries. Remember, your hormones are in a group chat. The brain kicks things off with a GnRH message, to which LH and FSH reply. The ovaries then respond to LH and FSH by sending estrogen and progesterone updates. Cortisol, though, is the friend that blows up the chat with emergency texts, disrupting the order. When this keeps happening all the time, the group stops talking about ovulation and starts focusing only on the “crisis” response. As a result, the cycle gets delayed, skipped, and/or chaotic.
As we try to better under the consequences of leaving cortisol, the stress hormone, on overdrive, stress-related thoughts and feeling are something that many of take to bed each night: the replay of what happened during the day, ruminating over past events, and making mental to-do lists for the days to come. Before we know it, we are waking up the next morning tired and still in need of more sleep.
Poor sleep due to shortened duration (<8 hours), disruption from LED light exposure at night, stimulant use such as caffeine close to bedtime, or due to difficulty turning off our brains for bedtime can interfere with the circadian system at multiple levels [1]. The circadian system is the body’s internal time-keeping network, essentially our biological clock. It coordinates biological processes on an approximately 24-hour cycle. Its primary role is to align our internal physiology, such as sleep-wake patterns, hormone release, metabolism, body temperature, and immune function, with the external day/night environment [1,2].
Inadequate or fragmented sleep alters the normal secretion patterns of key reproductive hormones due to disruption of the circadian clock. Gonadotropin-releasing hormone, luteinizing hormone, and follicle-stimulating hormone are normally released in precise pulses around the circadian clock [1,2]. This helps coordinate ovulation timing and cycle regularity. When sleep is insufficient, these pulses can become irregular or blunted, leading to delayed or absent ovulation and changes in cycle length. At the same time, poor sleep elevates cortisol, which can suppress reproductive hormone signaling and shift the body toward a state that prioritizes survival over reproduction: fight-or-flight mode [2,3].
Reduced sleep duration has been associated with lower luteal-phase progesterone levels, which may contribute to shortened luteal phases, heavier or more painful periods, and difficulty maintaining regular cycles [3,4]. Additionally, exposure to artificial or LED lighting at night and close to bedtime suppresses melatonin, a hormone that is essential for making someone “sleepy.” The lights trick the human brain into thinking that it is still morning, suppressing the sleepy hormone [5,6]. The main culprits of LED lighting are smart phones, TVs, laptops, and most lighting systems in living rooms and bedrooms. Lower melatonin levels have also been found to impair follicle quality and further disrupt estrogen-progesterone balance [4,5].
Over time, these hormonal disruptions can feed back into sleep itself. Imagine a thermostat that is supposed to cool a room when it gets too hot. Instead though, because of a wiring error, every time the room heats up, the thermostat triggers the heater to turn on. The heat causes the machine to glitch further, which turns the heat up even higher and creates a self-perpetuating cycle. Just like this, irregular cycles, premenstrual symptoms, and fluctuating estrogen and progesterone levels can worsen insomnia, night awakenings, and sleep quality, creating an unfortunate self-reinforcing cycle of poor sleep [5].
Where can I start? [6]
Keep the bedroom cool (65-68°F if possible), dark, and quiet. Use blackout curtains and cover or remove small LED lights. Even low-level light exposure at night can blunt the melatonin release.
Eat your first meal within 1–2 hours of waking and finish your last meal at least 2–3 hours before bed. Late-night eating can shift the ovarian and metabolic clocks out of sync with the brain, making the circadian clock think it’s earlier in the day than it actually is.
Use the same 30-60 minute routine nightly, such as a warm shower, stretching, reading, breathing, and/or light exercises. Repetition trains the brain to associate these cues with sleep onset, helping counteract any stress-related suppression of sleep and reproductive hormones.
Aim for 10-30 minutes of outdoor light within an hour of waking (no sunglasses if safe). In the evening, dim any household lights and avoid LED screens 1-2 hours before bed, or use blue-light–blocking glasses/night mode. This preserves melatonin, which supports both sleep quality and the hormone cycle.
Try to stop caffeine at least 8-10 hours before bedtime (earlier if you’re sensitive). Even caffeine 6 hours before bed can fragment sleep and reduce slow-wave deep sleep, indirectly raising cortisol and disrupting the estrogen–progesterone balance.
“There, that’s the last email for today.”
It’s still 7:30PM, but I put the laptop away and dim the lights.
At 10:30PM, when I climb into bed after a warm shower, I quickly fall into a deep sleep …
References
- Romans, S. E., Kreindler, D., Einstein, G., Laredo, S., Petrovic, M. J., & Stanley, J. (2015). Sleep quality and the menstrual cycle. Sleep Medicine, 16(4), 489–495. https://doi.org/10.1016/j.sleep.2014.12.001.
- Bassett, S. M., Lupis, S. B., Gianferante, D., Rohleder, N., & Wolf, J. M. (2015). Sleep quality but not sleep quantity effects on cortisol responses to acute psychosocial stress. Stress, 18(6), 638–644. https://doi.org/10.3109/10253890.2015.1087503.
- Hachul, H., Andersen, M. L., Bittencourt, L. R. A., Santos-Silva, R., Conway, S. G., & Tufik, S. (2010). Does the reproductive cycle influence sleep patterns in women with sleep complaints? Climacteric, 13(6), 594–603. https://doi.org/10.3109/13697130903450147.
- Kennedy, K. E. R., Onyeonwu, C., Nowakowski, S., Hale, L., Branas, C. C., Killgore, W. D. S., Wills, C. C. A., & Grandner, M. A. (2022). Menstrual regularity and bleeding is associated with sleep duration, sleep quality and fatigue in a community sample. Journal of Sleep Research, 31(1), e13434. https://doi.org/10.1111/jsr.13434.
- Jeon, B., & Baek, J. (2023). Menstrual disturbances and its association with sleep disturbances: A systematic review. BMC Women’s Health, 23(1), 470. https://doi.org/10.1186/s12905-023-02629-0.
- Huberman Lab. (2021). Scicomm Media LLC, https://www.hubermanlab.com/newsletter/toolkit-for-sleep.
