During perimenopause, at least two-thirds of women experience hot flashes, which typically continue for three to five years before tapering off. The cause may be erratic hormone levels. When they spike or plunge abruptly, mixed messages may be sent to the hypothalamus, the part of the brain that regulates body temperature. Your brain may mistakenly decide that you’re too warm; therefore it turns on its cool-down mechanisms and a flash is born.
"The theory is that women who get hot flashes have a much narrower thermo neutral zone, which is the temperature range at which you’re comfortable — not shivering, not sweating," says Jan Shifren, MD, director of the Vincent Menopause Program at Massachusetts General Hospital, in Boston.
At least, that’s what researchers think. "Research is ongoing, but nobody truly knows yet why women get hot flashes," Shifren says.
What we do know is that hot flashes are more likely to occur in women who smoke, are overweight or obese, or feel stressed or anxious; one study found that financial worries can trigger hot flashes. Also, women who experienced childhood abuse and neglect are significantly more likely to experience hot flashes, according to a 2008 study.
Blood glucose level may even play a role, according to Sharon Dormire, PhD, RN, a nurse researcher at the University of Texas at Austin. "In rats, you can induce hot flashes by reducing blood sugar," Dormire says. She has launched a study to determine whether the same thing happens in women.
Preliminary results suggest a link. "As blood glucose declines between meals, flash frequency increases," Dormire says. Falling levels during sleep may also trigger night sweats. Keeping glucose stable by eating more frequently may help stave off hot flashes, she says.
Soy-based foods, herbs, and vitamin supplements are sometimes recommended to reduce hot flashes, but evidence for their efficacy is mixed. If hot flashes or night sweats are wrecking your quality of life, talk with your doctor. A variety of medications can help, including low-dose birth control pills, estrogen therapy, antidepressants, and the antiseizure medication gabapentin (Neurontin). Of course, you should always ask about the risks, benefits, and side effects of each.
Originally published in MORE magazine, October 2008.
Want the latest beauty, fashion and lifestyle tips? Click here to sign up for our fabulous weekly newsletter!