Hot flushes and night sweats are the hallmarks of menopause, occurring in approximately 75 percent of postmenopausal women, with 25 percent of these women being severely affected. Symptoms may resolve in 2–5 years yet the median duration for hot flushes regularly occurring in the body is 7 years.
So what causes these hot flushes and why do women in menopause experience them?
The technical term for hot flushes is vasomotor symptoms. Vasomotor instability refers to a condition characterised by the inability to regulate blood vessel constriction and dilation, leading to unpredictable and often extreme fluctuations in body temperature.
During vasomotor instability, women may experience sudden and intense heat sensations, sweating, and flushing, often accompanied by a rapid heartbeat.
A hot flush is a subjective sensation of extreme heat associated with objective signs of cutaneous vasodilation and a subsequent drop in core body temperature. Women with oestrogen deficiency, like women in perimenopause and menopause, have a narrower thermoneutral zone. They have sensations of extreme heat despite a small increase in core body temperature.
Peripheral vasodilation and sweating help to dissipate heat. Recent literature describes how in postmenopausal women, there is an enlargement or growth of KNDY neurons in the hypothalamus. These neurons express Neurokinin B which appears to induce hot flushes.
Neurokinin B (NKB) is a neuropeptide, a small protein-like molecule that acts as a neurotransmitter in the nervous system. NKB plays a significant role in the hormonal changes that occur during menopause. The primary influence of NKB during this stage is related to its involvement in the regulation of reproductive hormones, particularly within the context of the KNDY (kisspeptin/neurokinin B/dynorphin) neuron system in the hypothalamus.
Neurokinin B is implicated in the control of body temperature. It acts on certain areas of the brain that are involved in thermoregulation, influencing the body's response to changes in temperature.
As women approach menopause, there is a decline in the production of reproductive hormones such as estrogen and progesterone. NKB, along with other neuropeptides like kisspeptin and dynorphin, contributes to the complex regulation of gonadotropin-releasing hormone (GnRH), which in turn influences the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These hormonal changes are associated with common menopausal symptoms such as hot flashes, mood swings, and changes in menstrual cycles.
As one 47-year-old woman stated, “They strike at the most inconvenient times – during meetings, in the grocery store, you name it. It's like an internal firecracker show.”
48-year-old Linda also reflected, “I thought hot flashes were just a quick, mild inconvenience. The reality? They hit you like a furnace, and there's no escaping them. I definitely underestimated the intensity.”
Poor sleep is a common consequence of these vasomotor symptoms, particularly in menopausal and perimenopausal women. Vasomotor instability can affect sleep because of night sweats, increased alertness or arousal due to the sudden onset of hot flushes, fragmented sleep, insomnia and daytime fatigue.
One female, 54 said, “Insomnia during menopause is like having a Netflix subscription but nothing you actually want to watch. Wide awake at 3 AM with my thoughts like, 'Why am I composing novels in my head right now?’”
“Sleep disturbances are a big one for me. I used to be a solid sleeper, but now it's like my body decided to trade a good night's sleep for frequent awakenings.” Stated another woman, 52.
Karen, also 52, explained, “The night sweats hit me hard last week. I woke up drenched, changed my sheets, and tried to go back to sleep. But then it happened again. I felt like I was in a never-ending cycle of changing sheets and battling the heat.”
The Phenxx Cooling Canvas is cool to the touch and keeps the sleeper dry from night sweats and cool despite hot flushes. The Thermocool pillow range cools the head and along with it the rest of the body. The range has been specially designed for menopausal to get a deep cool night's sleep.
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References
Harper, J. C., Phillips, S., Biswakarma, R., Yasmin, E., Saridogan, E., Radhakrishnan, S., C Davies, M., & Talaulikar, V. (2022). An online survey of perimenopausal women to determine their attitudes and knowledge of the menopause. Women's health (London, England), 18, 17455057221106890. https://doi.org/10.1177/17455057221106890
Mira. (2022, August). Menopause is a part of our story—let’s talk about it. Menopause (miracare.com)
NSW Government. (2023, 23 October). Menopause services. NSW Health. https://www.health.nsw.gov.au/women/Pages/menopause.aspx
Genitourinary syndrome of menopause. Prevalence and quality of life in Spanish postmenopausal women. The GENISSE study. Moral E, Delgado JL, Carmona F, et al. Climacteric. 2018;21:167–173.
Genitourinary syndrome of menopause: an overview of clinical manifestations, pathophysiology, etiology, evaluation, and management. Gandhi J, Chen A, Dagur G, Suh Y, Smith N, Cali B, Khan SA. Am J Obstet Gynecol. 2016;215:704–711.