Hot flashes, the most commonly reported symptom related to menopause, are experienced by up to 85 percent of menopausal women. Hot flashes occur when there is a decrease in previously well established circulating estrogen levels. The decline in estrogen is thought to affect the temperature control center in the brain, resulting in a turning on of the body's heat-losing mechanism. Blood flow is directed to the skin, which causes a visible flush, a sensation of heat, perspiration and a measurable drop in body temperature. Thus, a chill may be experienced afterwards. Hot flashes vary in frequency and intensity and can be stimulated by stress, spicy foods, caffeine, alcohol and warm external surroundings. Night sweats are hot flashes that occur at night and can be a cause of significant sleep disturbances. Some physicians believe that women who have a sudden menopause created by surgical removal of the ovaries may experience more severe hot flashes.

Hot flashes usually decrease in severity over the first two to three years after the menopause and subside after five years in the majority of women. However, up to one-third of women report hot flashes occurring for more than five years. The impact hot flashes have on a women's life is variable and depends on the interplay of hormonal changes as well as psychological, social and physical demands of her life.