Whenever I mention to a group of women that I’m a Sleep Scientist, I can say that on most occasions, someone will tell me how terrible their sleep is, that they are exhausted, and that they are at their wits’ end. Yet many brush this off with a shrug, assuming that it’s something they should be expected to deal with, that there is no help. Why should it be this way? Why should women be expected to just put up with the feelings of exhaustion, brain fog, changes in mood, sleep and our bodies, and carry on as normal? These changes are hallmarks of the menopausal transition, and this physiological thunderstorm can affect every aspect of our lives: performance at work, motivation, cognition, relationships, and general well-being (to name a few).
Having just watched Davina McCall’s excellent programme on the menopause (1), I felt more pressing than ever the need to open up the communication channels about perimenopause in the hope that enhancing our everyday understanding of what can be expected during this time of life can enable the perimenopause to be better recognised. That recognition throughout society may pave the way to a more accepting workplace culture, an understanding from clinicians, and ultimately, the development of new treatments for managing the symptoms that so many women experience. So I thought I’d contribute to these conversations by dispelling what I know about this critical time point, in my area – sleep. *note that I am not a clinician but a sleep scientist – you should always discuss your personal circumstances with a clinical professional and this blog is for an understanding of the scientific research only.
The Menopausal Transition and Sleep
The menopausal transition, also known as perimenopause, is a time replete with physiological changes, particularly vasomotor symptoms (hot flushes and night sweats) and depression (amongst others) - changes that dramatically affect sleep. In fact, the most symptomatic changes we see in sleep in women start during the perimenopause and continue post-menopause (2). More than a third of women report experiencing more sleep disturbances during menopause compared to pre-menopause, and up to 60% of post-menopausal women report difficulties in maintaining sleep, akin to insomnia (3, 4). Night-times are fraught with awakenings which can be one of the most frustrating experiences of this time. Awakenings can be triggered by hot flushes and night sweats, as well as sleep-disordered breathing (SDB), which are all common during the menopausal transition and post-menopause. Hot flushes and night sweats may precipitate the development of insomnia, and exacerbate pre-existing insomnia.
Some of these changes in sleep may be accounted for by the ageing process, or other clinical conditions that impact sleep. For example, ageing is associated with increases in the need to urinate at night, pain, anxiety, depression, and weight gain. Sleep disturbances such as Sleep Disordered Breathing (SDB) or Restless Legs Syndrome (RLS) are also more prevalent in women, particularly so during the menopausal transition and post-menopause (5, 6). However, the mechanisms underlying this are unclear and may be associated with other factors related to ageing, rather than the menopause per se. On the contrary, some of the sleep disturbances present at this time are specific to the hormonal changes that characterise the menopausal transition.
We see reductions in oestrogen and progesterone during the perimenopause, and it is possible that these changes interfere with the neurochemicals controlling the sleep drive, though research is unclear as to the precise mechanisms involved linking reductions in these hormones and poor sleep quality. Oestrogen decline may also affect our internal body clock known as our circadian rhythm. Studies have shown that post-menopausal women have an earlier secretion of melatonin in the evening (a hormone that readies the brain for sleep) compared to women in the menopausal transition (7), possibly contributing to earlier bed-times and early morning awakenings. It is likely that this shift to earlier bed and rise times begins in the perimenopause as oestrogen starts to decline.
Oestrogen insufficiency is also related to hot flushes. Hot flushes are characterised by sudden increases in core body temperature in the upper body, increased blood flow to the skin, and increased heart rate. Hot flushes typically last around 5 minutes, but it can take much longer for body temperature to return to normal, and the return to normal may feel like a chill. It is partly the chill and wet bedclothes from sweating that can interfere with sleep. During the menopausal transition, a large proportion of nocturnal hot flushes are associated with an awakening (8). You may wonder what comes first, the hot flush, or the awakening, yet research on this is mixed. One study showed that around 80% of hot flushes preceded or occurred at the same time as an awakening; and only 20% of hot flushes occurred after an awakening (8). However, another study showed that the majority of hot flushes occur after an awakening (9). Hot flushes that trigger awakenings may be more likely to occur in the first half of the night. This is because Rapid Eye Movement (REM) sleep, which is more abundant in the second half of the night, has thermoregulatory effects, suppressing hot flushes (10).
Perimenopause may also be a risk factor for (SDB), particularly obstructive sleep apnoea (OSA). Several studies have shown a higher prevalence of SDB in women post-menopause compared to pre-menopause (11). This raises the question as to the potential role of reproductive hormones in respiration. Progesterone is a respiratory stimulant (12), having effects on the neural control of respiration and excitatory effects on major muscles responsible for the dilation of the upper airways (11). Thus, it may be hypothesised that SDB may be more likely during the perimenopause due to declining levels of progesterone, coupled with increased abdominal fat distribution. However, a recent review of the literature demonstrated that the evidence is less clear cut, that SDB during and following menopause may be related to other factors such as the general ageing process, and that further research is needed before we can draw conclusions about the role of declining reproductive hormones in peri- and post-menopausal SDB (11).
Whilst awakenings, insomnia, hot flushes and SDB may be influenced by hormonal changes during the peri- and post-menopause, sleep disturbances may also be further exacerbated by external factors that may occur during this time. For example, poor sleep could be due to daily life stresses, such as caring for young children and teens, dealing with the stress that arises when older children move away from the family home, job-related stress, or caring for elderly relatives. Stress and anxiety contribute to the development of insomnia (13, 14), leading to a vicious cycle of anxiety, poor sleep and night-time awakenings. Disrupted sleep can also contribute to the development of mood disturbances such as depression, which increases in prevalence in women during the menopausal transition (2). Managing stress and anxiety is fundamental to healthy sleep at any stage of life, particularly so during the perimenopause when women are faced with numerous physiological, behavioural, and environmental challenges.
In the next blog in this series, I outline some of the evidence-base for managing sleep during the perimenopause and beyond.
References:
1. Channel 4. Davina McCall: Sex, Mind and the Menopause. UK: Channel 4, 2022.
2. Shaver JL, Woods NF. Sleep and menopause: a narrative review. Menopause 2015;22:899-915.
3. National Institutes of Health. National Institutes of Health State-of-the-Science Conference statement: management of menopause-related symptoms. Annals of Internal Medicine 2005;142:1003-13.
4. Joffe H, Massler A, Sharkey KM. Evaluation and management of sleep disturbance during the menopause transition. Seminars in Reproductive Medicine 2010;28:404-21.
5. Heinzer R, Marti-Soler H, Marques-Vidal P, et al. Impact of sex and menopausal status on the prevalence, clinical presentation, and comorbidities of sleep-disordered breathing. Sleep Medicine 2018;51:29-36.
6. Manconi M, Ulfberg J, Berger K, et al. When gender matters: restless legs syndrome. Report of the “RLS and woman” workshop endorsed by the European RLS Study Group. Sleep Medicine Reviews 2012;16:297-307.
7. Toffol E, Kalleinen N, Haukka J, Vakkuri O, Partonen T, Polo-Kantola P. Melatonin in perimenopausal and postmenopausal women: associations with mood, sleep, climacteric symptoms, and quality of life. Menopause 2014;21:493-500.
8. Bianchi MT, Kim S, Galvan T, White DP, Joffe H. Nocturnal Hot Flashes: Relationship to Objective Awakenings and Sleep Stage Transitions. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine 2016;12:1003-9.
9. Freedman RR, Roehrs TA. Lack of sleep disturbance from menopausal hot flashes. Fertility and Sterility 2004;82:138-44.
10. Freedman RR, Roehrs TA. Effects of REM sleep and ambient temperature on hot flash-induced sleep disturbance. Menopause 2006;13:576-83.
11. Lindberg E, Bonsignore MR, Polo-Kantola P. Role of menopause and hormone replacement therapy in sleep-disordered breathing. Sleep Medicine Reviews 2020;49:101225.
12. Bayliss DA, Millhorn DE. Central neural mechanisms of progesterone action: application to the respiratory system. Journal of Applied Physiology 1992;73:393-404.
13. Alvaro PK, Roberts RM, Harris JK. A systematic review assessing bidirectionality between sleep disturbances, anxiety, and depression. Sleep 2013;36:1059-68.
14. Pillai V, Roth T, Mullins HM, Drake CL. Moderators and mediators of the relationship between stress and insomnia: stressor chronicity, cognitive intrusion, and coping. Sleep 2014;37:1199-208A.