The researchers looked at data from more than 3,200 women aged 40-75. To be part of the study, the women had to have no period or spotting for one year.
The researchers split the women into four groups, ranging from no hot flashes to severe hot flashes.
After taking into account various demographic and health characteristics, the researchers found that women who had severe and moderate hot flashes felt they were in worse health than women with no symptoms.
For women with severe hot flashes, their ability to work effectively and be productive was seriously affected.
In fact, the annual costs associated with this added up to $1,100 for the mild group and $6,500 for the severe group.
About 40% of women have hot flashes for more than seven years, and up to 15% have hot flashes for longer than 15 years.
The researchers found that the effects of the hot flashes were especially significant for women whose symptoms lingered for many years.
Judith Volkar, MD, from the Cleveland Clinic in Ohio, says the results are "not a terrible surprise for most ob-gyns." Hot flashes really do severely affect a woman's quality of life. "It was nice that this was actually the first study to talk about how quality of life affects work productivity," she says.
The study results from the 2010 U.S. National Health and Wellness Survey are published in the journal Menopause.