What Causes Hot Flashes?

Jan 2, 2023
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Medically reviewed by: 
Leah Millheiser, MD

Hot flashes are one of the most common symptoms of menopause. And for the roughly 80% of women who experience them, they can be seriously distressing. Hot flashes interrupt sleep, disrupt work, scramble daily routines, and more. 

But what causes hot flashes? Although they’re still being studied, researchers believe they’re caused by changes in the brain that result from falling estrogen levels during menopause. In this piece, we’ll explore the complex chemistry behind hot flashes—and what you can do about them.

What Are Hot Flashes?

Hot flashes (sometimes called hot flushes) are an intense sensation of heat that’s typically focused on the face, head, neck, and chest. They come on abruptly (often with no warning) and typically last anywhere from 30 seconds to 5 minutes. Hot flashes can cause sweating and flushing, and may leave you chilled afterwards. Research shows that hot flashes actually raise your temperature and cause increased blood flow all over your body.

Hot flashes (along with mood changes, insomnia, and vaginal dryness) are one of the four core menopause symptoms. Doctors sometimes refer to hot flashes as a vasomotor symptom of menopause (VMS). They are incredibly common, affecting over 80% of people during menopause—but they’re not yet fully understood by medical science.

What Are the Symptoms of a Hot Flash? [H2]

The most prominent symptom of a hot flash is a feeling of heat that spreads through your chest, neck, and face. For some people, it’s a creeping sensation that starts in the core and spreads through the whole body. The feeling has been likened to a blast of heat from the sun, or standing in front of an open furnace. Here are some other effects of hot flashes that many people experience:

  • Flushed appearance: The spike in body temperature can make you look flushed, as if you just sprinted up a flight of stairs.
  • Red, blotchy skin: Depending on your skin tone, hot flashes can leave you looking red and blotchy.
  • Rapid heartbeat: Your heart may beat faster. Researchers have found that heart rate typically jumps by 8 to 16 beats per minute during a hot flash.
  • Anxiety: Hot flashes and anxiety are linked in complex ways. For some people, anxiety can trigger a hot flash and vice versa.
  • Chilled feeling afterwards: After the hot flash relents, your body has released a lot of heat and you may be very sweaty. This can cause clamminess and chills as your body temperature drops.

When Do Hot Flashes Start?

Hot flashes typically begin during perimenopause—the gradual transitional phase between your reproductive years and menopause. During this time, your body begins running out of egg cells, causing your body’s production of estrogen to fluctuate. This sudden drop in estrogen triggers the neurological changes linked to hot flashes. (More on this shortly.)

There is a broad range of “normal” ages at which hot flashes begin. The most common age range is 45-49 years old (when 35% of people begin experiencing them). But for a surprisingly large number of people (30%), hot flashes begin even earlier, in the 40 to 44-year-old range. Smaller (but not insignificant) numbers of people begin experiencing hot flashes after age 50 (21%) or under age 40 (14%).

How Long Do Hot Flashes Last?

On average, hot flashes last for 7.4 years. But it’s important to understand that many different factors can influence this number. Race and ethnicity are very significant factors—for African American women, hot flashes last an average of 10.1 years. Lifestyle factors like low exercise levels, high BMI, and cigarette smoking are also associated with longer hot flash duration.

What Causes Hot Flashes?

Hot flashes begin in the brain. Specifically, they seem to originate in a region called the hypothalamus. The hypothalamus is sometimes called “the body’s thermostat,” as it plays a crucial role in regulating your core temperature. During menopause, when your natural estrogen levels begin falling, the hypothalamus seems to undergo significant changes. This is no surprise, as the brain (and specifically the hypothalamus) is highly sensitive to estrogen and rich in estrogen receptors. 

These changes seem to cause some sort of glitch in the hypothalamus, triggering it to send out inappropriate signals to the rest of the body. In other words, your brain tells your body that it is very hot (even when it isn’t), and your body reacts by trying to quickly vent a lot of heat. This causes blood vessel dilation, a spike in heart rate, a sensation of overheating, and sometimes profuse sweating. 

Researchers still don’t know exactly how or why estrogen fluctuation causes this sort of malfunction, but there are several lines of evidence suggesting that it does. First, any event that drops your estrogen level can trigger hot flashes. That includes natural menopause, surgical menopause (i.e. menopause induced by a surgery such as removal of the ovaries), and the use of estrogen-blocking medications (such as tamoxifen). And second, medications that stabilize your estrogen levels (like menopausal hormone therapy) are the gold-standard treatment for preventing hot flashes.

It’s important to note that falling estrogen, rather than low estrogen, seems to trigger the neurochemical changes that cause hot flashes. After all, most people do cease to have hot flashes some time after menopause, when estrogen has stabilized at a low level.

Common Hot Flash Triggers

For many people, hot flashes are triggered by certain activities and environments. Of course, everyone is different; things that trigger hot flashes for you may be perfectly fine for other people, and vice versa. But here are some of the most common factors that patients, doctors, and researchers have linked with hot flashes.


A hot environment—such as a car, bedroom, or office—can trigger hot flashes by raising your body temperature. Elevating your temperature via exercise can also be an issue. (Of course, exercise also offers many health benefits and is still a great idea during menopause!)


That cold brew may energize you—but it can also trigger hot flashes, some people find. Tea, energy drinks, and chocolate may be similarly risky.

Spicy Food

The chemical that makes food spicy—called capsaicin—interacts with your nerve cells in a way that tricks your body into thinking it’s experiencing heat. That’s why spicy food can make you sweat, and possibly why it triggers hot flashes in some people.


Alcohol has a complex relationship with hot flashes. Some studies find that it increases hot flash risk, and some find just the opposite. Like other hot flash triggers, you’ll simply need to observe how alcohol affects you personally and proceed with caution.


Anxiety, stress, and hot flashes all seem to be linked. And that’s no surprise—cortisol (the stress hormone) may be one of the underlying factors triggering hot flashes. Protecting your mental health will likely pay dividends for hot flashes and other menopause symptoms.

How to Prevent (And Manage) Hot Flashes

For many people, hot flashes are an unavoidable part of menopause. That said, certain lifestyle adjustments may help you reduce hot flashes and manage them more effectively when they do arise. Here are some of the best strategies.

Keep a Fan Handy

A small electric fan (or even a hand fan) can work wonders during a hot flash. Try keeping one at your bedside, in your handbag, or at your office desk. Fans with mist spray attachments are even better.

Stay Hydrated

Carry an insulated bottle of ice water with you and stash a few around your house. Staying hydrated may help prevent hot flashes—and when they do occur, you’ll be happy to have a chilled beverage available.

Dress in Layers

Wear light, layered clothing made of breathable fabrics. This will make it easy to strip away a few layers when a hot flash strikes. Aim for loose-fitting garb that doesn’t restrict your circulation, as tight clothing can be a hot flash trigger.

Keep Your Home Cool

Warm environments are a major hot flash trigger, so try turning down the heat (or turning up the AC) a few notches. Even if you need a little extra clothing to stay comfortable (e.g. a light scarf in the winter), you can always remove it when a hot flash arises.

Exercise Regularly

The evidence is mixed on whether exercise helps prevent hot flashes. Some research has found that it is helpful, while other research has not. Either way, it is well-established that exercise can improve other menopause-related issues (such as mood changes, weight changes, and improvement in bone mass), which will improve your holistic health. And that will leave you in a better mental and emotional place for managing the stress of hot flashes.

Stop Smoking

We know this one’s tough, but it’s never too late to quit smoking. Cigarette smokers tend to have a more difficult menopause experience when it comes to symptoms. And while the research isn’t definitive, quitting smoking may ultimately ease your hot flashes.

How Are Hot Flashes Treated?

Menopausal Hormone Therapy

The gold standard treatment for hot flashes is menopausal hormone therapy (MHT). MHT uses estrogen—delivered via patch, cream, vaginal insert, or oral medication—to supplement your natural hormones. This supports your falling estrogen level and helps to restore normal function to your hypothalamus, thus preventing hot flashes where they begin. Progesterone is also often prescribed as part of the MHT regimen to protect the lining of the uterus from the effects of estrogen.

MHT has been proven effective for treating hot flashes in about 80% of cases, and people typically see relief within 2-4 weeks of beginning treatment. Hormone therapy also helps relieve many other menopause-related issues, including insomnia, vaginal dryness, mood shifts, skin and hair changes, and more.

Non-Hormonal Medications

Menopausal hormone therapy isn’t for everyone. For instance, people with a history of certain reproductive cancers (e.g., breast, uterine, ovarian) may not be able to safely use estrogen therapy. Others may simply prefer not to take hormonal medications. Fortunately, there are other effective hot flash treatments available in these cases, such as selective serotonin reuptake inhibitors (SSRIs) and selective norepinephrine reuptake inhibitors (SNRIs).

SSRIs and SNRIs were originally developed to treat depression and anxiety. By increasing the available serotonin in the brain, they have a positive impact on mental health. But as the use of SSRIs became widespread, they proved to have another benefit: reducing the frequency and severity of hot flashes. Clinical trials have proven that non-hormonal SSRI and SNRI medications are effective in up to 60% of cases.

As a hot flash treatment, SSRIs are typically prescribed at a lower dose than they are when used for depression or anxiety. There is currently only one SSRI that is FDA-approved for hot flash treatment (paroxetine, brand name Brisdelle). But several others are prescribed by healthcare providers on an off-label basis.

Over-the-Counter Options

A number of herbal supplements may have some efficacy in treating hot flashes—specifically black cohosh and Swedish flower pollen. It’s important to note that these are not FDA-approved hot flash treatments and more research still needs to be done to evaluate their safety and efficacy. Be sure to work closely with your healthcare provider if you’re using these supplements to manage your hot flash symptoms.

The Bottom Line

Hot flashes can be a major nuisance of the menopause transition and if you’re struggling with them, you’re not alone. The good news is that you can take steps to address the issue at its root. That includes menopausal hormone therapy, SSRI or SNRI medications, over-the-counter options, and behavioral changes that will help you manage the experience of hot flashes. Most importantly, be sure to work with a trusted healthcare provider, who can guide and support you every step of the way.