8 in 10 menopausal women experience hot flashes. Here's what causes them.

Every woman who reaches midlife will experience menopause and the 7-14 years that precede it known as perimenopause. During that transitional time, their ovaries will gradually stop working, contributing to decreased production of hormones such as estrogen and progesterone. This can lead to many of the unwanted symptoms that are associated with menopause and perimenopause.

These include night sweats, fluctuations in body weight, menstrual changes, mood shifts, and diminished cognitive function such as memory lapses and difficulty concentrating. 

Another of the most common symptoms associated with this time is hot flashes, as "approximately 70% of women will experience them at some point during the menopause transition," says Rebecca Thurston, PhD, a professor of psychiatry and a menopause researcher at the University of Pittsburgh.

What are hot flashes?

Hot flashes are episodes of intense heat that are often accompanied by sweating and flushing, Thurston explains. "They typically last a couple minutes, and occur randomly throughout the day and night." 

To many women, hot flashes "feel like a sudden rush of intense heat that starts in the chest and moves up into the neck and face," explains Dr. Ruta Nonacs, a perinatal and reproductive psychiatrist at Massachusetts General Hospital and an instructor at Harvard Medical School. The experience, she adds, can be "dramatic," leading to sleep disturbances in many women. 

Thurston says that hot flashes are the body's attempt to dissipate heat caused by rapid drops in certain reproductive hormones that impact the hypothalamus, which houses the thermoregulatory centers of the brain.

These drops in hormone production occur naturally in menopause and perimenopause, but sometimes other factors can trigger hot flashes. These include migraines, UTIs, neurological disorders such as Parkinson's disease and multiple sclerosis. "Hyperthyroidism, inflammatory diseases like lupus or rheumatoid arthritis, and even some cancers like lymphoma can also cause them," says Dr. Mary Jane Minkin, a practicing OB-GYN and a clinical professor at Yale School of Medicine.

Overconsumption of caffeine, spicy foods, and heart and blood pressure medications have also been shown to trigger hot flashes in some people. 

Do all women experience hot flashes? 

When triggered by such medical conditions or medications, hot flashes can happen to any women, and even men. In men, hot flashes can be triggered by erectile dysfunction medication and treatments related to prostate cancer. 

But hot flashes don't happen to every woman going through menopause of perimenopause. About 70% of perimenopausal women experience them and close to 80% of menopausal women get them as well, says Dr. Jewel Kling, associate director of women's health for Mayo Clinic in Arizona. About 30% of these women experience them frequently and "describe their hot flashes as severe," she says.

"Some 20% will get no flashes at all and we have no idea why they are so lucky," Minkin adds. 

Independent of menopause, "some women get hot flashes during certain phases of the menstrual period," says Thurston, "However, that is less common than during menopause."

What is the most common treatment for hot flashes?

Treatments for hot flashes vary, depending on their severity, frequency and cause. "When women have milder symptoms, we suggest avoiding things that can trigger hot flashes, including hot or spicy foods, caffeinated beverages, alcohol, and we suggest that they wear lighter clothing or layers," says Nonacs.

But when symptoms are more severe, disrupt sleep, or affect one’s ability to function day to day, "there are a variety of medications that are effective," she says. These include antidepressants that modulate hormonal activity such as sertraline (brand name Zoloft) and fluoxetine (brand name Prozac). Though not FDA approved for that purpose, doctors often also prescribe gabapentin (brand name Neurontin) to treat hot flashes. 

"Last year, the FDA approved a new type of medication for the treatment of moderate to severe hot flashes called fezolinetant (brand name Veozah)," adds Nonacs.

Minkin says that herbal remedies and supplements can also be helpful. Low-dose estrogen replacement therapy may also be used when symptoms are severe or when other treatments are not well-tolerated or are ineffective. "We have many forms available these days which are really quite safe," she adds. 

"For some women, hot flashes are a mild annoyance, yet for others they are very disruptive to your life," says Thurston. "For the women really suffering with them, I would advise getting help."