The warning is non-existent. You wake up soaked. The thermostat says seventy. The air feels normal, except you’re sweating through your sheets.
Or it hits at work. Mid-presentation. A rush of heat climbs your chest. Your face burns. You wonder if the room can see you flushing.
This is the hot flash.
It is a rite of passage for most women navigating perimenopause or menopause. Menopause officially arrives after twelve months without a period. Hot flashes don’t respect that calendar. They start before. They linger after.
Here is what doctors know about why you are overheating.
Who gets hit?
It lasts anywhere from sixty seconds to five minutes.
Dr. Monica Christmas, an OB-GYN at the University of Chicago, says most women deal with these about five years post-final-period. She leads the university’s menopause program. She also directs medical affairs for the nonprofit Menopause Society.
Women have hated these for centuries. A French doctor named Jean Liebault documented them in 1582. We know more now than Liebault did. But experts still scratch their heads at the variability.
Why do some women get them?
Why do others not even know the word exists?
“I ask my patients, ‘Are you having hot flashes?’ and they say ‘I don’t think so,’ Christmas says. If you aren’t complaining? You probably aren’t having them. Not everyone does.
The brain’s thermostat is broken
Physiologically, it is not a fever. Your core temperature hasn’t actually skyrocketed.
The cause lies in the hypothalamus. The brain’s internal thermostat. As ovaries produce less estrogen approaching menopause, this part of the brain gets hypersensitive. It misreads the body’s temperature.
The hypothalamus thinks you are overheating. It panics.
To cool you down, it dilates blood vessels near the skin. It triggers sweating.
“The surge typically starts at the nipple line and moves up,” Christmas explains. You feel internal fire. Then comes the sweat. The body trying to fix a problem that doesn’t technically exist.
Not all flashes are the same
Four in five women experience these during the menopause transition. The American College of Obstetricians and Gynecologists estimates the prevalence. But the experience varies wildly.
Mild warmth. Or drenching sweat. Daytime flares. Or night sweats that ruin sleep.
Triggers are everywhere. Alcohol. Caffeine. Sugar. Processed food. Stress.
Black women often report worse outcomes. Their symptoms tend to be more severe. They last longer—sometimes up to eleven years.
And here is the scary part. Long-lasting hot flashes correlate with a higher risk of cardiovascular disease. Treating the flash doesn’t automatically fix the heart risk. But it signals a need for closer monitoring of blood pressure and cholesterol.
Why only some women? For decades, scientists blamed low estrogen. That explanation felt lazy.
If it was just about lacking estrogen, why do women with residual estrogen get them during perimenopause? Why don’t all low-estrogen women sweat profusely?
The new suspects
Neurotransmitters are to blame.
Not hormones. Chemicals.
When estrogen drops, certain neurons in the hypothalamus get noisy. Called KNDy neurons—pronounced “candy.”
They release three specific messengers. Kisspeptin. Dynorphin. Neurokinin B.
These signals mess with your body’s ability to regulate heat. This newer theory explains why not everyone suffers. It explains why perimenausal women with some estrogen still get hit.
How to stop the fire
If you are one of the 75 to 80 percent dealing with this, or even the 10 percent who never find relief, you have options.
Estrogen therapy helps many. But not all can take it. A history of blood clots? Breast cancer? Skip it.
The discovery about KNDy neurons birthed new drugs. These don’t add hormones. They block the signal that says heat now.
The FDA approved Veozah in 2023. Its generic name is fezolinetant. It blocks the neurokinin-3 receptor. That single block calms the thermostat.
Lynkuet arrived in 2025 under the name elinzanetant. It does double duty. Blocking neurokinin-1 and neurokinin-3. Two points of failure for the heat signal.
Old drugs work too. SSRIs. SNRIs. Gabapentin for nerve pain. Oxybutynin for bladder control. Doctors use them off-label for flashes.
Stress matters. Calming the central nervous system via hypnosis or cognitive behavioral therapy reduces symptoms.
Christmas knows stress triggers her own flashes. Calming the brain helps calm the heat.
See a doctor
Don’t just wait it out.
Hot flashes can signal other things. Thyroid disorders. Infections. Even cancer. A check-up is wise.
Treatment exists. You do not have to sweat this out. Literally.
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