The hot flash is a sudden sensation of heat typically experienced by women during their menopausal years, although they have been reported among young women during various phases of the menstrual cycle. Flashes (also called flushes) are the most common complaint of women in the menopause transition. The heat sensation generally begins in the chest and radiates to the face, head, and arms. Women may also report feeling palpitations or anxiety with hot flashes. Other sensations reported include feeling nauseated, pressure in the head or chest, and a feeling of suffocation. Some women who experience hot flashes also complain of a reduced ability to concentrate; however, the relationship between hot flashes and memory is not well understood. At times, women report having night sweats and not hot flashes, although the two terms refer to the same physiological phenomenon.
For researchers, clinicians, and even the casual observer, hot flashes can be identified by the visible changes that accompany them, including skin flushing, increased skin temperature, and sweating. These characteristics provide the basis for assessment of hot flashes through measurement of skin and central body temperature, measurement of skin moisture, and analysis of skin conductance for clinical or research purposes.
In the United States, 75% to 80% of women undergoing the natural course of menopause and 95% to 100% of women whose ovaries are surgically removed experience hot flashes. Generally, hot flashes occur in women 40 to 60 years of age, with 87% experiencing them daily and about 30% reporting more than 10 flashes per day. Hot flashes are usually experienced over a period of 1 to 5 years but may last for more than a decade. Some women experience only one flash per month, whereas others have one per hour; alternatively, some 15% to 20% of postmenopausal women do not experience any hot flashes during the menopausal transition. Distress associated with having hot flashes varies among women from those that are barely noticeable to severe episodes of flushing, sweating, and feeling hot. Severe hot flashes can significantly disrupt activities of daily living, including work and sleep. In addition to being disruptive, hot flashes may be embarrassing in social situations.
Although prevalent during the menopausal transition, the cause of hot flashes is still not well understood. The hot flash is known to be related to estrogen decline as the number of follicles diminishes in the aging ovary. However, estrogen does not directly cause hot flashes. It appears that estrogen decline alters basic processes in the brain, which leads to the hot flash. These relationships are currently under investigation.
Various factors that can trigger hot flashes have been identified. These include consumption of hot drinks, spicy foods, alcohol, or caffeine as well as smoking cigarettes. Such identifiable triggers can be controlled to reduce hot flashes.
There are currently two effective treatments available for women experiencing hot flashes. Hormone replacement therapy (HRT) is the gold standard in treatment of menopausal hot flashes; HRT has been the cornerstone of therapy since the 1950s. It is the only therapy for hot flashes approved by the U.S. Food and Drug Administration (FDA). HRT generally reduces the frequency and intensity of hot flashes but may eliminate them completely for the duration of hormone use. Black cohosh, an herbal supplement, has also been demonstrated to be effective in treating hot flashes. Eight clinical trials have shown both the safety and effectiveness of black cohosh. Other treatments reported to reduce hot flashes are acupuncture, vitamin E supplements, exercise, and biofeedback. However, scientific evidence to support use of these therapies is lacking.
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- North American Menopause Society. (2003). The menopause guidebook: Helping women make informed healthcare decisions through perimenopause and beyond. Cleveland, OH: Author.
- North American Menopause Society, http://www.menopause.org
- Women’s Health Initiative, http://nhlbi.nih.gov/whi/indehtml