Are my hot flushes a sign of menopause or PMS?

Who hasn’t fought over the thermostat at home? Whether we like an enveloping warmth or a brisk cool atmosphere, temperature is very important to us as human beings. Believe it or not, there exists an actual thermostat within our brains as well. It exists for the sole purpose of our survival rather than comfort and is located on an organ called the hypothalamus. The hypothalamic thermal nucleus maintains our bodies within a temperature range that allows our cells to perform the vast array of processes that make use of energy and function, and keep us alive.

When the bounds of temperature are crossed, the hypothalamic thermal nucleus instructs our body to take actions that bring us back into normal range. That is why we shiver when we are cold; the activity raises our body temperature. It is also why we sweat when we are hot; as the liquid evaporates from our skin it provides a cooling effect.

Hot flushes are another mechanism for the body to get rid of unwanted heat. It may seem counterintuitive, since the nature of a hot flush is that it makes us feel hot, red and uncomfortable. What is actually happening is a complex nervous system response that dilates small blood vessels just under the skin so that they can release the heat they carry into the atmosphere. The result is a red appearance on the face that sometimes extends down to the neck and chest, that may be accompanied by sweating. It can sometimes be uncomfortable or distressing to experience.

How do hot flushes relate to menopause?

Around 80% of people going through menopause will experience hot flushes.¹ For some, it is a short-lived, minor inconvenience, and for others it lasts several years and greatly affects their quality of life.

Hot flushes can start in the transition time while you still have a normal menstrual cycle, or they can occur after your periods have stopped. They may involve suddenly getting a very, very red face and neck, feeling very hot and sweaty, and symptoms perhaps lasting a full 30 minutes.

Scientists believe that hot flushes occur due to a sudden drop in the body’s oestrogen levels

Although the exact mechanism of action is poorly understood, scientists believe that hot flushes occur due to a sudden drop in the body’s oestrogen levels. This drop somehow tightens the normal temperature variation that is acceptable to your body, so even slight changes in current temperature prompt a large bodily response to accommodate it and bring us back to homeostasis (a normal temperature range).

This bodily response can include dilation of blood vessels in the face, and sweating.² These symptoms are associated with menopause since the stopping of your periods is a result of your ovaries no longer producing eggs, and, therefore, oestrogen.

Can you get hot flushes when you aren’t menopausal?

Though not the most prominent symptom of PMS and not quite as severe, around one in five people who menstruate may complain of a degree of hot flushes because the second half of their monthly menstrual cycle also involves a drop in oestrogen levels.³ This causes a slight rise in body temperature, which is why some tools to help people conceive use temperature-taking as a way of judging when you have ovulated.

This temperature rise occurs in conjunction with PMS symptoms usually after ovulation, through to the week before your period starts. This drop is not sustained, nor is it as significant as during the menopause, and the slight raise in body temperature rarely presents as a hot flush like those that menopausal women experience.

Slight hot flushes are not a common complaint of PMS symptoms, and little research has been done into why they may occur and how they can be treated effectively, other than to regulate the hormone cycle through the use of a contraceptive pill. No research has been done into why some people may experience symptoms of PMS and others not.

How to tell whether your hot flushes are menopause or PMS?

In order to tell the difference, we need to take into account a variety of different factors. We start by considering age. Menopause, on average, occurs around the age of 51 but can start from 45. Primary ovarian insufficiency, or the gradual failing of the ovaries, occurring earlier than this isn’t very common – affecting about 1 in 1000 people with wombs under the age of 30 and 1 in 100 under the age of 40.⁴ How old were your mother, aunts or sisters when they went through the menopause? Is there a family history of early menopause?

If you are in your twenties, fit and well, and with no medical issues, it would be really quite unusual to have severe hot flushes

If you are still pre-menopausal and menstruating regularly, and you have no other symptoms pointing towards premature menopause, then your hot flushes may be related to PMS. If you are of peri-menopausal age (also called the climacteric, or the year or two during which your periods become irregular and then stop altogether with the onset of menopause) then your hot flushes are most likely related to the menopause.

It is really important to bear in mind the distinction between feeling a bit warm, and an actual hot flush. Essentially, if you are in your late 40s or early 50s, your periods are becoming erratic, and you are having hot flush symptoms, it is likely they are related to the menopause.

Before that, if you are perhaps in your twenties, fit and well, and with no medical issues, it would be really quite unusual to have severe hot flushes and you may need to see your doctor to check if you are at risk of premature ovarian failure. Otherwise, with all else being normal, it is probably related to PMS.

Overall health and other conditions

Other things to consider when working out what your hot flushes mean include your overall health and current medications that you may be taking. Are you having treatment for cancer? Chemotherapy, and also agents used for breast cancer that target oestrogen receptors, can cause you to enter an early menopause. Some breast cancers grow under the influence of oestrogen, so one treatment your doctor may have started you on is an anti-oestrogen drug such as tamoxifen.

Have you had multiple surgeries on your ovaries? Surgical damage can sometimes result in an earlier menopause, though the damage would have to be significant and affect both your ovaries.

Do you have an autoimmune condition such as hypothyroidism or lupus? Though poorly understood, a cluster of auto-immune diseases breeds an immune system that accidentally attacks its own normal cells and, though very rare, this can happen to your ovaries as well.

Do you smoke? Smokers have been found to enter the menopause earlier than people who don’t smoke. Perhaps the defining factor is, do you still have your period? Regular periods are a sign of normal hormonal balances, and not early menopause.

If you are not menopausal and are concerned about hot flushes and what they mean, a visit to your doctor can help. Depending on your history your doctor may look for other PMS symptoms and start you on a pill to help mitigate them – or they may order some blood tests (follicular stimulating hormone and luteinising hormone) to review the balance of hormones in your body. If you are menopausal and are finding your hot flushes debilitating, there are many different treatment options available. If your GP is unsure what to prescribe for your symptoms you may be referred to a menopause clinic for management.

Featured image shows a woman in a pale pink top getting a glass of water from the tap. The image is cropped so you can only see her hand, arm, and the glass.

Last updated May 2023
Next update due 2026

Disclaimer: This content is designed to provide general information and is not a substitute for medical advice. Medical opinion, practice and routine may vary from country to country and may change from time to time. The author is not liable for the results of misuse or inappropriate application of the information. If you are an individual who chooses to access this information, you should not rely on the information as professional medical advice or use it to replace any relationship with your doctor or other qualified healthcare or social care professional. For medical concerns, including decisions about medications and other treatments, individuals should always consult their doctor or, in serious cases, seek immediate assistance from emergency personnel. Individuals with any type of medical condition are specifically cautioned to seek professional medical advice before beginning any sort of health treatment. Individuals with specific queries or concerns should seek appropriately qualified medical advice. Clinicians must use their own judgement when interpreting this information and deciding how best to apply it to the treatment of patients.