Hot flashes: why they happen, how long they last, and how to calm them

A wave of heat that suddenly rises into your chest, neck, and face. Your heart races, your skin flushes, sometimes you break into a sweat… followed by a chill. If you are over 40, there is a good chance you are already familiar with this sensation, or will be soon.

Hot flashes are one of the most well-known symptoms of perimenopause and menopause. To understand what is really happening in your body, and most importantly how to soothe them, we spoke with Carole Minker, a pharmacist, author, and expert from our series Génération Péri. Her message is clear: there is a wide range of solutions, with or without medication, and everyone can find what works for them.

What is a hot flash?

Carole describes it as: "a wave of heat that primarily floods the upper body," the chest, head, and sometimes the arms, "as if you had just walked into an oven." A bit like a sudden fever, but one that arrives without warning.

It can occur:

• during the day, at work, in meetings, or while commuting;
• at night, when it often takes the form of night sweats that wake you up (we discuss this in our article on night sweats).

For some women, they remain rare and easy to manage. For others, they occur very frequently, several times a day, and become truly difficult to live with.

How many women are affected?

According to Carole, 70 to 80% of women in perimenopause or menopause have experienced or are experiencing hot flashes, with varying frequency. She also encourages us to look at the glass as half full: 20 to 30% of women will never have them, or very few.

They can start during perimenopause, sometimes very sporadically, well before periods stop. If you have hot flashes without being in this life stage, there are other causes: we detail them in our article on hot flashes without menopause.

Why do we get hot flashes? The chain reaction

This is the most enlightening part of the episode. Carole explains that the mechanism is complex, which is precisely why we can take action on several levels.

1. The starting point: hormones

It all begins with fluctuating estrogen levels, which is typical of perimenopause. This hormonal imbalance triggers others. Carole specifically emphasizes the thyroid : the brain-thyroid axis is closely linked to the brain-ovary axis and the brain-adrenal axis. The thyroid plays a major role in regulating body temperature. It first needs everything it requires to function, and in this hormonal context, it can go into overdrive. "You have to look at the body as a whole."

2. The brain's thermostat goes haywire

This hormonal imbalance then disrupts the hypothalamus, our brain's thermostat. It tricks it into thinking, incorrectly, that the body is overheating.

3. An unnecessary emergency cooling response

To "release" this heat that isn't actually there, the body triggers an emergency cooling response: blood vessels near the skin's surface dilate (this is known as vasodilation). Blood rushes to the skin on your arms, neck, and face: this is what causes a hot flash.

4. The rebound effect: shivering

Since the body wasn't actually too hot, it then finds itself too cold. The blood vessels constrict, and you feel chilly. This is why many women experience shivering right after a hot flash.

5. A nervous system that amplifies everything

Finally, Carole mentions brain inflammation and the role of neurotransmitters, which amplify this signal triggered by a false alarm. This is also why stress is a known trigger for hot flashes.

Hormones, thyroid, brain thermostat, blood vessels, nervous system: a hot flash is a chain reaction. Each link is an opportunity to help calm them down.

How long do hot flashes last?

It varies greatly. A major American study, the SWAN study, followed over 1,400 women with frequent hot flashes for several years: they lasted for a median of 7.4 years, with significant differences depending on when they started. We explain everything in our article how long can you have hot flashes.

Triggers to be aware of

Certain situations tend to trigger hot flashes for many women:

• stress and anxiety;
• alcohol, coffee, spicy or very hot foods;
• an overheated room, clothing that is too warm or made of synthetic materials;
• tobacco.

You won't necessarily have the same triggers as everyone else. Tracking your hot flashes for a few weeks (time, intensity, what you were doing just before) can help you identify yours.

How to calm hot flashes: all the solutions

"The idea is to have a range of solutions that you can draw from depending on your needs," explains Carole. Here are the main ones, from the simplest to the medical.

Physical solutions, without ingesting anything

Perineal cryotherapy. This is the most surprising solution. It involves applying a cold gel pack to the perineum. According to Carole, bringing cold to a body that "thinks" it is overheating prevents it from triggering its cooling system. It is also said to have an anti-inflammatory effect and to stimulate the vagus nerve, which calms the nervous system. Its advantages: it's inexpensive, the pack lasts a long time, it's non-invasive, you don't ingest anything, and Carole is aware of no side effects, contraindications, or interactions. There are also small devices available today based on the same principle. Remember to protect your skin with a cloth: never apply an ice pack directly to the skin.

Cold on the neck. Another form of vagus nerve stimulation through cold: a cool pack on the side, back, or base of the neck.

Fans, air conditioning, lightweight clothing. Natural materials that let the skin breathe, and layers that are easy to remove. Carole points out that these actions relieve the sensation but do not act on the disrupted thermostat: they can be combined with other methods.

Calming the nervous system

Since the nervous system goes into overdrive, calming it helps to soothe the cascade. Carole suggests:

• theyoga and qi gong;
• theexercise and relaxation;
• the meditation,breathing and heart coherence.

Not everyone finds it easy to meditate, and that's perfectly normal: the idea is to try out several practices to find the one that works for you. The common thread among all these methods is that they stimulate the vagus nerve, the main nerve of the parasympathetic system, the "calming" part of the autonomic nervous system. This system operates automatically (digestion, temperature), and breathing is the only lever we can control voluntarily: that's why it's so useful.

Plants and supplements

Several options exist, with or without phytohormones:

• saffron, one of the most studied active ingredients, which acts on the nervous system;
• circulatory plants, such as red vine or witch hazel, which act on the blood vessels;
• phytoestrogen-rich plants, such as sage or red clover, which come with significant contraindications.

This series is made possible by Ginama, a brand of hormone-free supplements specializing in perimenopause, whose supplement dedicated to hot flashes is built around saffron. We detail all these options, and their precautions, in our article on plants for hot flashes, and on phytohormones in our article on phytoestrogens.

Hormone therapy

It remains the most effective treatment for intense hot flashes. It should be discussed with your doctor or gynecologist, who will evaluate your situation and medical history. If you are already on hormone therapy and the hot flashes persist, talk to them about it as well: it is up to them to make adjustments.

When should you consult a doctor?

Perimenopausal hot flashes are physiological, "explainable" as Carole says. But "that doesn't mean you have to just live with them." Consult a doctor:

• if they disrupt your sleep, your work, or your daily life;
• if they are accompanied by palpitations, dizziness, fever, or weight loss;
• if they appear outside of the typical perimenopause period;
• if you have a history of hormone-dependent cancer and are looking for a solution.

It is not inevitable

"Above all, don't just suffer through it. It is not inevitable," concludes Carole. Hot flashes are common, but they are not a stage to be endured in silence. Understanding the chain reaction is the first step to knowing where to take action. To understand this period as a whole, read our guide on perimenopause and find our content on perimenopauseandmenopause.

Discover the episode with Carole Minker

Discover the Generation Peri series

Key takeaways

• 70 to 80% of women in perimenopause or menopause experience hot flashes, but 20 to 30% will never have them, or almost never.
• They result from a chain reaction involving hormones, the thyroid, the brain's thermostat, blood vessels, and the nervous system.
• They can last for several years, averaging around 7 years according to the large SWAN study.
• Cooling techniques, calming the vagus nerve, herbs, supplements, and hormone therapy are all solutions that can be combined.
• If they are disrupting your life, talk to your doctor: you don't have to just put up with them.

FAQ

How can you calm a hot flash in the moment?

Cold helps: use a cold pack on your neck or perineum (wrapped in a cloth), drink cool water, or use a fan. Slow breathing also helps calm the nervous system.

Why do you feel cold after a hot flash?

Because the body triggered a cooling response even though it wasn't actually too hot. The blood vessels then constrict, and you start to shiver.

Are hot flashes dangerous?

In themselves, no. But they can significantly disrupt sleep and daily life. Consult a doctor if they are accompanied by heart palpitations, dizziness, or other unusual symptoms.

Can you have hot flashes before menopause?

Yes, they often begin during perimenopause, sometimes years before your periods stop completely.

What is the most effective treatment?

Hormone therapy is the most effective treatment for intense hot flashes; discuss this with your doctor. Other solutions exist for those who cannot or do not wish to take it.

The information in this article is for educational purposes only and does not replace professional medical advice. The Génération Péri series is produced in partnership with Ginama. Before taking any herb, supplement, or treatment—especially if you have a history of cancer, are currently undergoing treatment, or are pregnant—talk to your doctor or pharmacist.