One minute you’re perfectly comfortable. The next, you feel like someone turned the thermostat up 20 degrees.
Your face gets hot. Your chest starts sweating. You’re throwing off the covers—or looking around the room wondering, “Is anyone else hot, or is it just me?”
Welcome to one of the most common symptoms of perimenopause: the hot flash.
But why does it happen?
It’s not just because your estrogen is “low”
This is one of the biggest misconceptions about hot flashes.
During perimenopause, estrogen doesn’t simply decrease in a nice, predictable straight line. It fluctuates—sometimes dramatically. You may have plenty of estrogen one week and significantly less the next.
Those hormonal ups and downs affect your brain, particularly an area called the hypothalamus, which helps control body temperature.
Think of your hypothalamus as your body’s thermostat.
Before perimenopause, that thermostat is pretty forgiving. Your temperature can move up or down slightly without your brain getting concerned.
During perimenopause, the thermostat becomes much more sensitive.
Suddenly, a tiny increase in body temperature can make your brain react as though you’re overheating.
And then your body hits the emergency cooling button
Your brain basically says:
“We’re too hot. Cool everything down!”
Blood vessels near the surface of your skin widen so your body can release heat. That’s why your face, neck, and chest may suddenly feel warm or look flushed.
Then your sweat glands kick in.
A few minutes later, the hot flash may disappear almost as quickly as it arrived. And because your body just worked so hard to cool itself down, you might actually feel cold or chilled afterward.
At night, the same process becomes a night sweat—and can leave you awake, uncomfortable, and wondering why you’re changing pajamas at 3 a.m.
There’s also some fascinating brain chemistry involved (for all you science aficionados)
Scientists have discovered that certain brain cells called KNDy neurons play an important role in hot flashes.
These neurons help coordinate reproductive hormones and temperature regulation. Estrogen normally helps keep this system regulated.
As estrogen signaling changes during perimenopause, these neurons can become more active—particularly a signaling pathway involving neurokinin B.
The result?
Your brain can trigger a heat-loss response even though the room isn’t actually hot.
This discovery is especially interesting because it has led to newer nonhormonal medications that target the brain pathways involved in hot flashes.
So yes, you can have hot flashes while you’re still having periods
Absolutely.
Perimenopause can begin years before your final menstrual period. You may still have regular—or somewhat regular—periods and experience hot flashes, night sweats, sleep problems, mood changes, brain fog, or changes in energy.
That’s because perimenopause is a transition, not an overnight switch from “enough estrogen” to “not enough estrogen.”
Your hormones are changing, and your brain is adapting to those changes.
The good news? You don’t necessarily have to just live with them.
Hot flashes are common, but that doesn’t mean you have to suffer through them.
Depending on your symptoms and medical history, options may include lifestyle changes, menopausal hormone therapy, and several nonhormonal treatments such as OWL Balance Menopause Support.
Most importantly, understanding why hot flashes happen can make the experience feel a little less mysterious.
So the next time you’re standing in front of the freezer wondering why everyone else in the house seems perfectly comfortable, remember:
It may not be the room temperature. It may be your internal thermostat adjusting to the hormonal roller coaster of perimenopause.