When is a hot flash not just a hot flash? When it’s a window into future health—of your heart, your bones, your brain and your moods.
“We used to think that hot flashes were just an annoying quality-of-life issue, but now we are learning that they may signal something more about a woman’s health,” says psychiatry professor Rebecca Thurston, PhD, director of the Women’s Biobehavioral Health Laboratory at the University of Pittsburgh in Pennsylvania.
To be sure, just having hot flashes is no cause for concern. After all, in the transition into and through menopause, almost 70% of women experience them. Most of the time, they are merely uncomfortable.
THE VARIETY OF HOT FLASH EXPERIENCES
The trouble is, in the run-up to menopause, when your hot flashes start, when they eventually stop, and how severe they are may be emerging clues to future risks for heart disease, diabetes, osteoporosis, dementia and depression.
Here’s how to read those clues—and what to do about it.
As new research emerges, it’s becoming clear that many of our assumptions about hot flashes have been way off base. Hot flashes can start many years before menopause and last for many years after your last period is a distant memory…arrive and depart in a year or two…or never happen at all. Now, thanks to a long-term research project called SWAN—it stands for “Study of Women’s Health Across the Nation” and has followed about 3,300 women over 15 years—we’re getting the real story. While every woman experiences hot flashes differently, SWAN has identified four distinct trajectories…
- Early onset, with the first hot flash about a decade before the last menstrual period and ending after the last period.
- Later onset, with the first hot flash appearing about the time of the final period, persisting several years and later declining.
- The lucky few, who have just a few hot flashes around the time of the final menstrual period that don’t persist long afterward or never have hot flashes at all.
- Super flashers, who have frequent hot flashes from well before menopause and often well into the years afterward.
Women tend to fall fairly equally into these four groups, with the late-onset path being the most common (29%) followed by the lucky few (27%), super flashers (26%) and early onset (18%). SWAN and other studies are also uncovering key associations to health risks. Here’s what hot flashes tell us about….
A SWAN study has reinforced the connection. Women were asked to track their hot flashes and underwent ultrasound to determine the thickness of the walls of the carotid arteries in their necks—a good measure of atherosclerosis, which increases the risk for heart disease and stroke. Result: Women who reported more frequent hot flashes (at least every other day) had evidence of atherosclerosis. Also, a different SWAN study found evidence of atherosclerosis in women who had early-onset hot flashes.
Bothersome hot flashes made little or no difference. “We have more often seen effects for frequency than severity,” explains Dr. Thurston. But weight increased risk, she adds—if a woman was overweight or obese and had frequent or early-onset hot flashes, the heart risk connection was even stronger.
While the mechanisms aren’t well-understood, it may be that women who have less-than-healthy blood vessels (but not yet actual cardiovascular disease) may be particularly susceptible to troublesome hot flashes. So the hot flashes serve as a kind of early warning signal for heart disease risk.
Hot flashes may also be linked to bone density, osteoporosis and fracture risk. One Korean study found that women who had hot flashes, compared with those who never did, had lower bone density. That was true even after adjusting for other risk factors such as smoking, age, weight and exercise. (Lower bone density increases the risk that you’ll develop osteoporosis.)
A separate American study analyzed data from nearly 30,000 women (ages 50 to 79) followed for more than eight years at 40 different medical centers. None were taking hormone therapy. Those with moderate-to-severe hot flashes, compared with those with no hot flashes, were 78% more likely to have a hip fracture.
This research is more preliminary, but there may be a hot flash link to brain changes that may increase a woman’s risk for dementia. In a small study of 20 healthy midlife women who didn’t have cardiovascular disease and weren’t taking hormone therapy, hot flashes per se weren’t linked with dementia risk, Dr. Thurston and her colleagues have found. But women who had more night sweats—hot flashes during the nighttime—were much more likely to have high levels of “white matter intensities” in their brains. “White matter intensities are a marker of small vessel disease,” explains Dr. Thurston, “which is, in turn, a marker for increased risk for dementia.” These associations were not accounted for by sleep quality or quantity or hormone levels.
In a long-term Australian study, women who reported having severe, early-onset hot flashes were 55% more likely to develop type 2 diabetes during the 15-year follow-up period than women who had mild hot flashes. A separate SWAN study found that women who had hot flashes or night sweats tended to have more insulin resistance, a precursor to diabetes, than women without them.
DEPRESSION AND ANXIETY
Women who have more hot flashes and night sweats are more likely to suffer from negative mood, such as increased depression and anxiety. These relationships are likely bidirectional—that is, the hot flashes and night sweats cause negative mood, and the negative mood also makes the hot flashes and night sweats less tolerable. In some studies—but not all—disrupted sleep accounts for the associations between night sweats and depressed mood.
WHAT TO DO
The research on hot flashes’ links to overall health is still new, so it’s too early to draw firm conclusions about cause and effect. In some cases, early, frequent or severe hot flashes might be caused by underlying physiological problems—in other cases, especially with night sweats, bad hot flashes may just make it awfully hard to get a good night’s sleep.
But if your hot flashes are frequent or severe, make it a wake-up call to take better care of yourself. “Women who are having a lot of hot flashes or who started having them early should stay on top of their health,” says Dr. Thurston. “Watch your diet and remain physically active. Control cholesterol, triglycerides and blood pressure, and see your health-care provider at regular intervals for standard preventive health care.” And if you smoke cigarettes, get help so you can quit. Controlling your risk for these factors may help level the playing field, she says.
If you’re wondering whether treating your hot flashes will help minimize any or all of the above risks, well, unfortunately, there’s no evidence for that. But one thing is clear: There’s no reason to suffer. Hormone therapy, and nonhormonal medications and supplements, have been shown to reduce hot flashes, and mind-body disciplines such as hypnosis and cognitive behavioral therapy can be effective, too.
The best approach: Redouble your efforts to improve your health habits to both curb hot flashes and improve your long-term health. Regular vigorous exercise, along with a largely plant-based diet, may also help reduce hot flashes—and reduce your risk for these chronic diseases. And if treating your night sweats helps you get restorative sleep again, you’ll not only feel much better but will be doing your long-term health a world of good.