Sleep is a necessity. We should all be aware of that. But what happens when we sleep? Why is menopause such a hot time for insomnia? And why do we wake before the sun, wired and ready to rock?
Also, where is the sleep switch? I want to sleep, and I want to control when I go to sleep. Now.
Life, including our bodies, are made up of cycles; reproductive cycles, sleep cycles, cortisol cycles, breathing cycles, cardiovascular cycles – many cycles. As with all cycles in our bodies, there are multiple factors that influence the cycle in a ‘push or pull’ manner. In a sleep cycle, some factors encourage sleep and restfulness, and others encourage stimulation and wakefulness. The balancing act, along with timing, are key factors in a healthy sleeping pattern.
According to the experts, there are two sleep tendencies or cycles, in most people. The first cycle of sleepiness starts around the persons habitual bedtime and peaks between 3-6am. The second time of maximum sleepiness occurs 12 hours later, between 2-4pm. Interestingly, it has also been found that there are also two times of increased arousal or alertness. These periods occur between 10am-12pm, and again between 8pm-10pm. These times of arousal are referred to as the forbidden zones for sleep, as these are the times when individuals find it very difficult to fall asleep even when they are very sleepy. With this being said, everyone is unique and individual variations for the exact timing of these forbidden times and sleep times exist. Factors such as day/light, jetlag, stress and changes in a work schedule influence these times.
Interestingly, although probably not that surprisingly, women are different to men when regarding sleep. Unfortunately, women have twice the prevalence of sleep complaints than men. This may be due to many reasons (kids, work, stress, etc.), but the main one I want to focus on is sex hormones.
Interestingly, there seems to be a pattern to sleep disturbances and certain times in a menstrual cycle. A study of 630 menstruating women found that the most issues with sleep were observed at the beginning and the end of the menstrual cycle[1], notably when oestrogen is low or has dropped significantly. A separate study of 213 women found sleep issues occurring mid-cycle and at the end of a cycle[2], again notably when oestrogen is low or drops significantly. Each of these times (beginning, mid-cycle, and the end of a cycle) are times of hormonal fluctuations and it has been suggested, but not proven, that the fluctuations are the cause of disturbance, not necessarily the absolute numbers[3].
Looking at the sex hormones individually, we can see their potential for influence and benefits. Oestrogen plays a role in serotonin availability and use, strongly affecting and assisting sleep onset and quality. It also plays a role in increasing REM sleep cycles, increasing deep sleep, decreasing sleep latency, reducing awakenings, regulating body temperature (aiding sleep) and affecting cortisol levels, indirectly affecting sleep quality. These benefits agree with the studies mentioned above.
Unfortunately, a lack of oestrogen takes away these benefits – the temperature regulation is lost, making heat an interrupting and disturbing factor. The serotonin benefits are lost, reducing the ease of sleep onset and sleep quality. The REM and deep sleep benefits are lost, impacting the ease of waking or interrupted sleep. Menopause marks a time of low oestrogen, and poor sleep and waking unrested are common complaints.
Progesterone is the other main sex hormone and not surprisingly, it also plays a strong role in sleep quality. Progesterone is often considered the sleep-promoting hormone, or the relaxing hormone. This may be due to its effect on GABA, a neurotransmitter that aids in sleep and relaxation and/or due to its effect on providing hypnotic and sedative benefits through metabolic processes. Regardless of the ‘why’, we have personally seen the results. Many of the women we help, via progesterone supplementation, often comment on the generally welcome sedative or sleepy effect.
Interestingly, and to add to this, progesterone seems to be involved in breathing and respiration, being highlighted as a factor involved in aiding sleep apnoea and sleep disordered breathing[4]. After menopause, this benefit disappears and sleep apnoea and sleep disordered breathing in women raises to become a similar number as seen in men.
What does this mean for menopause?
About 20% of menopausal women sleep less than 6 hours per night, and between 40-56% of post-menopausal women report sleep problems[5]. Interestingly, and frustratingly, these sleep problems can come independent of hot flushes, night sweats or anxiety. You many simply find yourself unable to get to sleep (for no known reason), waking several times at night (for no known reason) or waking alert at a very early and dark time of the morning (for no known reason). Unfortunately, many women find themselves in the same position.
Several studies have investigated and found positive results for sleep improvements with bio-identical hormone replacement therapy[6]–[7]. Speak to the team at the Australian Menopause Centre if you want to discuss sleep issues, menopause and/or individually prescribed bio-identical hormone supplementation.
Moving away from the sex hormones and their direct impact, let’s consider some other options that impact sleep, and how menopause affects these.
Melatonin
Melatonin is a hormone that your brain produces in response to darkness. Its main job is to regulate night and day cycles, or sleep and awake cycles. When the sun goes down and darkness occurs, melatonin levels in the blood sharply rise and you begin to feel less alert, making sleep more inviting. Unfortunately, melatonin production gradually declines as we age, and this may impact the ease of falling asleep.
This impact is not menopause related, but it is definitely age related and seen in menopause.
Glucose
Your blood sugar control can affect your sleep. Unfortunately, menopause is a time of vulnerability to insulin resistance or high glucose levels, and this may impact your ability to sleep via increased feelings of warmth, irritability and unsettledness. Waking to urinate may also be linked, as your kidneys attempt to flush out excess glucose.
Cortisol
Cortisol is your stress hormone. Naturally, cortisol levels are low before bedtime and they spike in effort or relation to waking up. When you face stress your cortisol levels increase in attempt to keep you alert and efficient in staying alive. If your cortisol levels are elevated, your melatonin level (the sleepy hormone) is low, and your ability to go to sleep is also low. Ongoing stress or worry can heavily impact your ability and quality of sleep. Menopause can lead you to stressing and it’s important to prioritise stress reduction techniques.
If you have ever had issues with sleep, you can understand how far reaching poor sleep is. Every person, at every age should be mindful of their sleep and their sleep quality. Every woman in perimenopause or menopause needs to be extra mindful. Particularly if they want to breeze through menopause, keep their sanity and keep healthy relationships.
[1] Kravitz, H. M., et al. (2005). “Relationship of Day-to-day Reproductive Hormone Levels to Sleep in Midlife Women.” Archives of Internal Medicine 165(20): 2370-2376.
[2] Van Reen, E. and J. Kiesner (2016). “Individual differences in self-reported difficulty sleeping across the menstrual cycle.” Archives of Women’s Mental Health 19(4): 599-608.
[3] Baker, F. C. and K. A. Lee (2018). “Menstrual Cycle Effects on Sleep.” Sleep Med Clin 13(3): 283-294.
[4] Andersen, M. L., et al. (2006). “Effects of progesterone on sleep: a possible pharmacological treatment for sleep-breathing disorders?” Curr Med Chem 13(29): 3575-3582.
[5] Gava, G., et al. (2019). “Cognition, Mood and Sleep in Menopausal Transition: The Role of Menopause Hormone Therapy.” Medicina (Kaunas) 55(10).
[6] Gava, G., et al. (2019). “Cognition, Mood and Sleep in Menopausal Transition: The Role of Menopause Hormone Therapy.” Medicina (Kaunas) 55(10).
[7] Cintron, D., et al. (2017). “Efficacy of menopausal hormone therapy on sleep quality: systematic review and meta-analysis.” Endocrine 55(3): 702-711.
About The Author - Samantha Mainland
Samantha is a highly educated Naturopath having graduated from both Southern Cross University with a Bachelor of Naturopathy, and University of Tasmania with a Bachelor of Medicine Management with Professional Honours in Complementary Medicine.