Seven Years. Nobody Said Seven Years.
Body · The Reading Room, Vol. 36 · 8 min read · The real duration figures, the single thing that predicts your own, and what is worth doing with a number this size
Based on the published research of Nancy E. Avis, PhD — Professor, Department of Social Sciences and Health Policy, Wake Forest University School of Medicine, and a lead investigator on SWAN’s vasomotor-symptom research. Faculty profile
How long do hot flashes last has a real answer, and it is longer than the one in circulation. The useful part is not the average. It is what predicts which end of it you are on.
Somebody told you two years. It might have been a GP in a seven minute appointment, or a leaflet, or your own mother, who genuinely did not remember it lasting long.
You are now three years in, standing at the window of a meeting room with your back to everybody, waiting for it to pass so you can turn around.
And the question underneath the discomfort is not really about the heat. It is about the planning. How long do hot flashes last, actually, so that you can stop treating each month as the one where this finally stops.
The short answer: longer than two years, for most women. The Menopause Society puts the mean duration at seven to ten years, with individual episodes lasting one to five minutes.¹ The Study of Women’s Health Across the Nation found that frequent hot flashes last seven or more years for about half of women.² And the strongest predictor of your own duration is not age. It is when they started: women whose symptoms began before their final period averaged nine to ten years, while women whose symptoms began after it averaged about three and a half.³
The skim version
- Up to 80 per cent of women have some hot flashes or night sweats.¹²
- Mean duration is seven to ten years, and a single episode lasts one to five minutes.¹
- About half of women with frequent hot flashes have them for seven years or longer.²
- Starting before the last period predicts nine to ten years; starting after it predicts about three and a half.³
- Almost 30 per cent of women get hot flashes in their thirties, while their periods are still regular.²
How long do hot flashes last, and why was I told two years?
Because the two year figure predates the research that could answer the question.
Harvard Health describes the older belief as six to twenty four months, against current estimates of seven to eleven years.³ That is not a small correction. It is the difference between an inconvenience you sit out and a decade you might reasonably want to make a decision about.
The reason the old number survived is that measuring this properly is difficult. You need to follow the same women for years, through a transition whose start and end are only identifiable in retrospect. SWAN did that, which is why the numbers changed.²³
What that means practically is that a great deal of the advice in circulation, including some of it given to you personally, was calibrated to a duration that is not the real one. Being told to wait it out is reasonable advice for eighteen months. It is a different proposition at seven years, and the decision about whether to treat it deserves to be made against the true figure.
What predicts which end of the range you are on
Timing, mostly. Not severity, not fitness, not how well you are handling it.
The SWAN finding that matters here is about onset. Women who had their first hot flashes while still cycling, before the final period, went on to have them for an average of nine to ten years. Women whose first ones arrived after the final period averaged around three and a half.³ So an early start is the signal for a long run, which is the opposite of what most people assume.
There are consistent differences by background too. SWAN found Black and Native American women reported the most frequent and most bothersome hot flashes, and Chinese and Japanese women the fewest.² Harvard reports African American women with the longest average duration, more than eleven years, and Japanese and Chinese women with roughly half that.³
The Menopause Society adds two associated factors rather than triggers: more abdominal fat is linked to a higher likelihood, particularly in younger women, and both current and past smoking raise the risk. Surgical menopause tends to produce more frequent and more severe symptoms than natural menopause.¹
What the research found
SWAN is a long-running study of women of different races and ethnicities followed through the menopause transition, which is what allows it to report duration relative to the final period rather than relative to age.²³ Its headline duration figures and The Menopause Society’s independent estimate of seven to ten years land in the same place, from different directions.¹²³
The limitation: these are cohort averages and the spread underneath them is wide. A median of seven years means a substantial number of women are done in three and a substantial number are still going at twelve, and no figure here tells you which one you are. The onset finding narrows it usefully and does not settle it. Anyone offering you a precise personal forecast is going further than the data does.
If the calculation you keep running is how much longer you can hold everything together at this level, that is a bigger question than the heat. The Quiet Audit is a private ten-minute pass through what the week is actually costing. Start here.
What the number changes
| If it is two years | If it is seven to ten | |
|---|---|---|
| The sensible response | Sit it out | Decide whether to treat it |
| At work | Manage it quietly | Worth changing something structural |
| What each month means | Nearly over | One of many, so pace it |
| What you conclude when it does not stop | Something is wrong with me | This is the ordinary length |
The bottom row is the one worth having. A great deal of the private distress here comes from measuring a normal duration against a wrong benchmark. Managing them in a meeting room is its own set of problems, and the night version turns out to run in a surprising order.
What to do with a number this size
Treat the decision as a decision, and take it to somebody who can act on it.
If the honest expectation is seven years rather than eighteen months, then not treating it is also a choice with consequences, and it deserves the same scrutiny as treating it. That is the shift the real number makes.
The Menopause Society lists hormone therapy as the most effective treatment for bothersome hot flashes and the FDA-approved first line, available as pills, patches, sprays, gels or vaginal rings.¹ It also lists two non-hormonal medications with FDA approval, low dose paroxetine and fezolinetant, and three non-drug approaches with evidence behind them: weight loss, cognitive behavioural therapy, and clinical hypnosis.¹ That last group is worth knowing about, because it is often left out of the conversation entirely.
The sentence worth taking with you, roughly as written: My hot flashes started before my periods stopped, they are affecting my sleep and my work, and I would like to talk about treatment options. Three facts and a request. It fits in the time you will be given, and it moves the appointment from sympathy to a decision. The wider picture on hormone therapy is worth reading before you go.
The source for this piece
Nancy E. Avis, PhD
Professor in the Department of Social Sciences and Health Policy at Wake Forest University School of Medicine, and a lead investigator on the Study of Women’s Health Across the Nation (SWAN), including its landmark analysis of hot flash duration.
What we read: Avis, N. E., et al., “Duration of Menopausal Vasomotor Symptoms Over the Menopause Transition,” JAMA Internal Medicine (2015) — the study behind the SWAN duration figures cited above.
Where to follow her work: Faculty profile
Who else has measured this
SWAN’s duration findings are not the only line of evidence on how long this phase actually costs a woman at work and at night.
Rebecca C. Thurston, PhD (Faculty · Scholar · UPMC expert profile), Professor of Psychiatry at the University of Pittsburgh, has led extensive research connecting frequent hot flashes to cardiovascular risk markers, giving the duration numbers here a second reason to matter beyond comfort.
A duration study and a cardiovascular-risk programme, both pointing the same way: this is not a symptom to simply wait out, and how long it runs is a clinical fact worth having.
Somebody told you two years. The real number is longer.
Questions worth having an answer to
How long does one hot flash last?
One to five minutes, according to The Menopause Society.¹ That is the episode itself. The recovery afterwards, the damp shirt, the wait before you can turn back around in the room, is not counted in that figure and is a large part of what makes them costly at work.
I am 38 and getting them. Is that possible?
Yes. SWAN found almost 30 per cent of women have hot flashes in their thirties while still having regular periods.² Being too young for this is one of the most common wrong assumptions in the whole subject, and it is worth raising with a clinician rather than dismissing.
Do they stop suddenly or fade?
Usually they taper, becoming less frequent and less intense over months rather than ending on a date. Which is one reason the two year figure persisted: the ending is gradual and easy to misremember as having happened sooner.
Does anything I do make them last longer?
The associations reported are with abdominal fat and with smoking, current or past.¹ Those are associations rather than proven causes, and neither of them is a reason to read a long duration as something you brought on yourself.
The one move
Work out one date and write it down: roughly when the first hot flash happened, and whether your periods were still regular then. That single fact is the best available predictor of how long this runs, and it is the one a clinician will ask for.
If the answer is that you have been holding this at work for four years without telling anyone, that is worth seeing written down. The Quiet Audit is a private pass through what your week is actually spending. Start here.
On the researcher. Nancy Avis is a health-policy researcher, not a prescribing clinician: SWAN’s duration figures describe cohort averages, and any decision about treatment belongs in a conversation with a prescriber who knows your history.
Sourcing, disclosure and disclaimers
This is not medical advice. Blue Leaf Journal publishes general information for a general readership. Nothing here is a diagnosis, a treatment recommendation, or a substitute for care from a clinician who knows your history.
We are not clinicians. Blue Leaf Journal is an independent publication. We read published research and translate it. The findings belong to the researchers and institutions named and linked above; the plain-English rendering is ours, and so is any error in it.
No affiliation and no endorsement. Blue Leaf Journal is not affiliated with Nancy E. Avis, Rebecca C. Thurston, Wake Forest University School of Medicine or the University of Pittsburgh. None of them has reviewed, approved or endorsed this article, and none of them is responsible for it. They are cited because their published work is the evidence for what it says.
No commercial relationship. Nobody named above paid for or was paid for this coverage. There are no affiliate links, no sponsored placements and no gifted products in this article.
How this was checked. Every figure above is drawn from the primary papers, each linked in the references, and can be verified there. Sources were checked on 6 September 2026. If you find something we have got wrong, write to norawhitfield@blueleafjournal.com and we will correct it and say that we did.
References
1. The Menopause Society. Hot Flashes, patient education. Read the page
2. Study of Women’s Health Across the Nation. SWAN Fact Sheets, 2023 edition. Read the fact sheets
3. Harvard Health Publishing. Menopause-related hot flashes and night sweats can last for years. Read the article
Nora Whitfield writes the Body desk at Blue Leaf Journal, where the working rule is that a mechanism you can name is easier to live with than one you cannot. She reads the limitations section before the conclusion, and passes on what she finds there.
Written by Nora Whitfield for Blue Leaf Journal. Updated: 3 September 2026.
