Hot flashes at night
How long will my hot flashes last?
Tell the page what your periods were doing when the flashes began, and see how long they lasted for women who started at the same stage in the largest long-term study.
For half the women in the SWAN study, frequent hot flashes and night sweats lasted more than 7.4 years in all, and 4.5 years after the final period. The biggest clue to your own run is when they started: women whose flashes began while their periods were still regular had them longest, and women whose flashes began after their periods had stopped had them for the shortest time.
The NHS gives a broader answer for menopause symptoms as a whole: usually 7 to 9 years, sometimes longer. The estimate below narrows that down using the one fact about your flashes you probably remember: whether your periods were still regular, changing or over when they began.
Estimate your hot flash years
Think back to when hot flashes or night sweats started coming most weeks, on about half the days or more.
What the SWAN figures mean
SWAN, the Study of Women's Health Across the Nation, enrolled 3,302 women aged 42 to 52 at seven US sites and saw them about once a year from 1996 to 2013. The 2015 duration analysis in JAMA Internal Medicine followed the 1,449 who reported frequent hot flashes or night sweats, defined as six or more days in the previous two weeks. Women who started hormone therapy before their flashes became frequent were left out, so the figures describe flashes that ran their own course.
Every number here is a median. Half the women in a group stopped having frequent flashes before that point and half carried on after it, so it tells you where the middle of the group sat and nothing about where you will sit.
| Flashes began | In total | After last period |
|---|---|---|
| Regular or changing periods | over 11.8 | 9.4 |
| Periods already stopped | 3.4 | not given |
| Whole study | 7.4 | 4.5 |
The "over 11.8" is not a typing slip. More than half of the earliest starters were still having frequent flashes at the last point the study could measure, so the true middle lies somewhere beyond it. The paper's summary gives no separate figure for women whose periods had nearly stopped, so the estimate shows them the figures for the study as a whole. Their run will likely fall between the two extremes.
Who had them longest
Background mattered almost as much as timing. African American women had the longest total run, a median of 10.1 years, and Japanese and Chinese women the shortest. The National Institute on Aging also says African American and Hispanic women have hot flashes for more years than white and Asian women. Women in SWAN also tended to have them longer if they were younger when the flashes began, had less formal education, felt more stressed, paid closer attention to bodily sensations, or had more anxiety or low mood at the time. Those are patterns across a group, and the study did not test whether changing any of them shortens a run.
The long tail after menopause
The Penn Ovarian Aging Study followed 255 women through natural menopause over 16 years. Eight in ten had moderate or severe hot flashes at some point. On average those lasted nearly five years after menopause, and more than a third of the women still had flashes of that strength ten or more years after it.
An Australian survey of 2,000 women aged 40 to 65, published by Gartoulla and colleagues in 2015, looked at older ages. Among women aged 60 to 65, 42% still had hot flashes, mostly occasional and mild. Only 6% of that age group found them moderately to severely bothersome, against 28% of postmenopausal women under 55 and 15% of those aged 55 to 59.
A worked example
Take a made-up reader whose night sweats began in 2022, when her periods had started to come at odd intervals but had not stopped. She chooses "Periods changing but still coming", types 2022 and picks "Under 55".
The page puts her with SWAN's earliest starters. Over half of them still had flashes most weeks 11.8 years after they began, which from 2022 takes her past 2034, and the middle of the group kept them for 9.4 years after the final period. It adds that 28% of postmenopausal women under 55 in the Australian survey found their flashes moderately to severely bothersome. None of that says her flashes will last until 2034. It says that if they are still there in 2030, she is in good company.
My take
I'd start with timing and give it more weight than the findings on ethnicity or stress, because it is the one detail most women can recall without guessing. I'd judge the median as something to plan around, never a deadline. A woman who started early and expects two years will feel let down every season, while one who has the SWAN figure in mind can pace her decisions about the bedroom, her sleep and whether to see a doctor.
If you are unsure when your flashes became frequent, a few weeks of the printable night diary will at least show how often they come now. Sensors in one sleep-lab study counted more flashes than the women reported, so a written record beats memory.
When to talk to a doctor
You do not have to wait out a median. The NIA lists treatment options to discuss with a doctor when flashes wake you at night or get in the way of your day. Night sweats that start for the first time years after your last period, or come with a fever or weight loss you cannot explain, are a reason to see a GP, and our night sweats warning-signs checker goes through the NHS list. Our article on whether hot flashes stop after menopause covers what still breaks sleep as they fade, and everything else we have written on the subject is in the hot flashes at night section.
This estimate uses published group medians from SWAN (Avis 2015), the Penn Ovarian Aging Study (Freeman 2014) and an Australian survey (Gartoulla 2015). It describes what happened to groups of women and cannot say when your own hot flashes will stop. It is no substitute for medical advice.