The strongest data looking into this question comes from Sweden. Researchers investigated groups of women born in 1918 and 1930 and compared them with those born in 1954 and 1966. Over several decades, they interviewed these women about their experience with hot flashes when they turned 50.

They found that women of the more recent generations experienced significantly more frequent hot flashes than those born earlier. Thirty-five percent of women born later experienced daily hot flashes, compared with 24 percent of women from prior generations.

The question became: why?

Other studies have noted links tying certain aspects of health to hot flashes — for example, smoking and elevated BMI are associated with higher rates, and both factors have changed over the last 100 years. Stress level and medications like contraception and hormone replacement therapy also play a role.

So the researchers built a statistical model to adjust for these possibilities among the cohort of Swedish women. If any one of these factors could explain the difference in hot flashes across generations, that change would go away, or at least diminish.

But it didn’t. Even after accounting for things like BMI and medication use, women born later had nearly twice the odds of experiencing daily hot flashes than in prior generations.

Susan Reed, a physician-scientist in women’s health and professor emeritus in obstetrics and gynecology at the University of Washington, agrees with the study’s conclusions that women today are probably experiencing more hot flashes than in previous generations. She believes that it’s being driven by environmental, genetic and social factors that are difficult to tease apart.

“Menopause is like a big interwoven tapestry that brings together a lot of threads. It’s not a straight line connecting any two things,” she said.

One possibility is that women are becoming more likely to report hot flashes because how we view menopause has changed. We’ve come a long way since the term “la ménopause” was coined by a 19th-century French male physician. (He wrote a whole section in his textbook about how menopause causes hysteria.)

Women are now encouraged to talk more openly about their symptoms than in the past.

But if we accept that the women of the Swedish study reported their symptoms accurately for the purpose of medical research, we’re left searching for another explanation.

Much of what we know today about menopause comes from the Study of Women’s Health Across the Nation. SWAN began in 1994 and sought to understand the menopausal transition in an ethnically and racially diverse sample of women across the United States. It enrolled 3,302 women age 42 to 52 whose menses had not yet stopped and is still following them today.

This study is monumental in the world of women’s health — there are few studies like it (the Swedish study mentioned earlier involved mostly White, relatively lean women). From SWAN, we’ve learned that compared with White women, those with Chinese and Japanese backgrounds experience longer menstrual cycles, and Black women experience a longer menopause transition — with symptoms of hot flashes and night sweats lasting a median of about 10 years. The study also found that Black women were less likely to receive treatment for these symptoms than White women.

SWAN revealed that a range of factors — such as lower education level and higher stress and anxiety — were linked to women experiencing hot flashes and night sweats for a longer period.

According to Reed, knowing these associations is helpful. For example, treatments that are known to mitigate stress like cognitive behavioral therapy can improve hot flashes and night sweats. Some scientists also argue that environmental changes like pollution and rising global temperatures aggravate the perception of hot flashes.

But these factors are not the end of the story, especially when it comes to intergenerational differences. Rather, they’re likely markers of something else the science has yet to uncover.

One of these possibilities is epigenetic changes — or changes to our DNA that occur during our life span.

“Our DNA is more complex than just what gets passed down through our eggs and sperm,” Reed said. “There’s no question that the complexity of our environment today is modifying our DNA if we look at behavior through time and how organisms adapt.”

For instance, she explained, infants born to obese mothers experience modifications to their DNA that can increase their own risk of obesity and cardiovascular disease later in life. Scientists have observed unique epigenetic changes in patients who undergo menopause early and among those with worse hot flashes. But it remains to be seen precisely what is triggering such changes — and what role they might play in shaping women’s symptoms.

Experiencing menopause is a normal process, but suffering is never something we should normalize. If you’re bothered by your hot flashes and they’re diminishing your ability to enjoy your day-to-day life, talk to your physician and get help. Talking about your symptoms can clue your physician in to other potential risk factors — for instance, women with severe hot flashes have a higher chance of a heart attack or stroke. Find a physician who takes your symptoms seriously, and don’t brush your experiences under the rug.