Biochemical and Thermoregulatory Effects of Behavioral Treatment for Menopausal Hot Flashes

Although hormone replacement therapy is an effective treatment for menopausal symptoms, it is contraindicated for some women with an increased risk of cancer. It has previously been shown that postmenopausal women with hot flashes have elevated levels of central sympathetic activation. We therefore developed a behavioral relaxation procedure that significantly reduced hot flash frequency, presumably through the reduction of central sympathetic activation. Twenty-four postmenopausal women with at least five hot flashes per day were randomly assigned to receive eight 1-h sessions of training in paced respiration or alpha-EEG biofeedback (placebo). Pre- and posttreatment assessments of respiratory parameters and measurements of plasma 3-methoxy-4-hydroxyphenylglycol (MHPG: the main metabolite of brain norepinephrine), norepinephrine, epinephrine, and platelet α2-adrenergic receptors were performed. Ambulatory monitoring of skin conductance level and tidal volume (24 h) were used to assess the effects of treatment. Hot flash frequency declined significantly(p <0.001) for the paced-respiration group (9.5 ± 1.4/day pre vs. 5.5 ± 1.5 post) but not for the placebo group. There were no significant changes in any biochemical measure. In addition to the decline in hot flash frequency, the 24-h pattern of skin-conductance level was significantly altered for the paced respiration group. Thus the effects of paced respiration training do not appear to be mediated through reduced sympathetic activation but do result in thermoregulatory changes over a 24-h period.