Perimenopause symptoms
Hot flashes and sweating
Vasomotor symptoms during perimenopause
You know the feeling. A wave of heat rises through your chest and face without warning — at your desk, in a meeting, in the middle of the night. Within seconds you're flushed and sweating. Then, just as suddenly, a chill moves through you as your body tries to correct itself.
If this is familiar, you're not alone — and you're not imagining it. Hot flashes and night sweats are the most researched symptoms of the menopausal transition. They have a name — vasomotor symptoms — they have a well-understood cause, and they are experienced by the majority of women going through perimenopause.
Hot flashes are caused by a change in how your brain regulates body temperature. In the years around menopause, fluctuating oestrogen levels affect the hypothalamus — the part of the brain that acts as your internal thermostat. Research shows this thermostat becomes unusually sensitive during the menopausal transition. Your body responds by rapidly dilating blood vessels near the skin surface — causing the sudden heat and visible flushing. Then, as your core temperature drops below that narrow comfortable range, a chill follows.
A sudden wave of heat, typically felt first in the chest, spreading upward through the face and neck. Usually lasting between one and five minutes.
Hot flashes occurring during sleep. You may wake to find yourself damp or drenched, needing to kick off covers or open a window.
Sweating during the day without obvious cause — without exercise, without being in a warm environment.
A visible reddening of the face and neck during or after a hot flash, caused by blood rushing to the skin surface.
The cold feeling that often follows a hot flash as the body overcorrects after sweating.
Approximately 55% of women begin experiencing hot flashes as they enter perimenopause, with prevalence rising as the transition progresses. Up to 85% experience them at some point. A large longitudinal study published in JAMA Internal Medicine found that frequent vasomotor symptoms persist for a median of more than seven years in women who first experience them during perimenopause.
Warmth — a warm room, a hot drink, getting into a warm bed — can bring on a flash. Stress is another common trigger, as is alcohol, particularly red wine. Smoking is associated with more frequent and severe vasomotor symptoms. Sleep deprivation makes everything worse, including the experience of hot flashes themselves — creating a cycle that can be hard to break.
Hot flashes and night sweats are a legitimate reason to see a doctor. They directly affect sleep, concentration, mood, and quality of life — and effective treatments exist. When you go to your appointment, it helps to be specific: How often are they happening? Are they waking you at night? How much are they affecting your daily life?
Hot flashes and sweating is one of eight areas covered in the Thea Klara survey. You rate each symptom by how often it happens and how much it affects you — generating a one-page summary to bring directly to your appointment.
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Thurston RC, Joffe H. Vasomotor Symptoms and Menopause. Obstet Gynecol Clin North Am. 2011.
Avis NE et al. Duration of Menopausal Vasomotor Symptoms. JAMA Intern Med. 2015.
Bansal R, Aggarwal N. Menopausal Hot Flashes: A Concise Review. J Midlife Health. 2019.
de Zambotti M et al. Magnitude of the impact of hot flashes on sleep. Fertil Steril. 2014.
Thea Klara provides self-advocacy tools, not medical advice. This content has been written to help you understand and describe your experience. It is not a substitute for a conversation with a qualified healthcare professional.