Postmenopausal physiological changes.

The hallmark of menopause is the marked reduction of estradiol levels due to ovarian failure. This, among other factors result in hot flashes, the most common menopausal symptom. Hot flashes (HFs) can be measured objectively, both inside and outside the laboratory, using sternal skin conductance, an electrical measure of sweating.

Menopause and sleep.

An obese, 50-year-old woman complains of hot flashes, poor sleep, snoring, and daytime sleepiness. She states that these problems have bothered her for about 4 years. Her partner recently complained about her snoring and restlessness, prompting this visit.

Menopausal hot flashes: mechanisms, endocrinology, treatment.

Hot flashes (HFs) are a rapid and exaggerated heat dissipation response, consisting of profuse sweating, peripheral vasodilation, and feelings of intense, internal heat. They are triggered by small elevations in core body temperature (Tc) acting within a greatly reduced thermoneutral zone, i.e.

Temporal sequencing of brain activations during naturally occurring thermoregulatory events.

Thermoregulatory events are associated with activity in the constituents of the spinothalamic tract. Whereas studies have assessed activity within constituents of this pathway, in vivo functional magnetic resonance imaging (fMRI) studies have not determined if neuronal activity in the constituents of the tract is temporally ordered. Ordered activity would be expected in naturally occurring thermal events, such as menopausal hot flashes (HFs), which occur in physiological sequence.

Escitalopram treatment of menopausal hot flashes.

Objective: The aim of this study was to determine the effects of 10 and 20 mg/day of escitalopram on objectively recorded hot flashes and on the rectal temperature threshold for sweating.

Methods: Two studies were performed: 16 women received 10 mg/day and 26 women received 20 mg/day escitalopram for 8 weeks. They were randomly assigned in equal numbers to receive active drug or placebo in a double-blind fashion.

Heart rate variability in menopausal hot flashes during sleep.

Objective: The aim of this study was to determine if heart rate variability changes during hot flashes recorded during sleep.

Methods: This study was performed in a university medical center laboratory with 16 postmenopausal women demonstrating at least four hot flashes per night. Polysomnography, heart rate, and sternal skin conductance to indicate hot flashes were recorded in controlled, laboratory conditions.

Treatment of menopausal hot flashes with 5-hydroxytryptophan.

Objective: Much recent research has focused on nonhormonal treatments for menopausal hot flashes. The purpose of the present study was to determine the effects of 5-hydroxytroptophan (5-HTP), the immediate precursor of serotonin, upon menopausal hot flashes. Selective, serotonergic, reuptake inhibitors (SSRIs), which increase the amount of serotonin in the synaptic gap, have shown some promise in the amelioration of hot flashes.

Sleep disturbance in menopause.

Objective: To determine the sources of sleep complaints in peri- and postmenopausal women reporting disturbed sleep.

Design: A total of 102 women, ages 44 to 56 years, who reported disturbed sleep were recruited through newspaper advertisements. They were assessed with the Pittsburgh Sleep Quality Index and the Hamilton Anxiety and Depression Rating Scales.

Miniature hygrometric hot flash recorder.

Objective: To design and test a miniature ambulatory hot flash recorder that uses neither electrodes nor gel.

Design: In the first study, putative hot flashes recorded by using a relative humidity sensor were compared with patient event marks. In the second study, relative humidity recorded by using a complete prototype recorder was compared with sternal skin conductance recordings made on a Biolog recorder, as well as with event marks.

Effects of REM sleep and ambient temperature on hot flash-induced sleep disturbance.

Objective: To determine whether hot flashes produce sleep disturbance in postmenopausal women.

Design: This study was performed in a university medical center laboratory with 18 postmenopausal women with hot flashes, six with no hot flashes, and 12 cycling women, all healthy and medication free. Polysomnography, skin and rectal temperatures, and skin conductance to detect hot flashes were recorded for four nights.

Cortical activation during menopausal hot flashes.

Objective: To determine regions of brain activation associated with menopausal hot flashes and sweating.

Design: Controlled laboratory study.

Setting: University medical center.

Hot flashes: behavioral treatments, mechanisms, and relation to sleep.

Hot flashes are the most common symptom of the climacteric and occur in about 75% of perimenopausal and postmenopausal women in Western societies. Although hot flashes accompany the withdrawal of estrogen at menopause, the decline in estrogen levels is not sufficient to explain their occurrence. Elevated sympathetic activation acting through central alpha(2)-adrenergic receptors contributes to the initiation of hot flashes, possibly by narrowing the thermoneutral zone in symptomatic women.

Thermoregulatory effects of 3,4-methylenedioxymethamphetamine (MDMA) in humans.

Rationale: Although 3,4-methylenedioxymethamphetamine (MDMA; Ecstasy) has been reported to cause fatal hyperthermia, few studies of the effects of MDMA on core body temperature in humans have been conducted demonstrating increased body temperature. In rats, MDMA causes hyperthermia at warm ambient temperatures but hypothermia at cold ones.

Objectives: In this study, the physiological and subjective effects of MDMA in humans were determined at cold (18 degrees C) and warm (30 degrees C) ambient temperatures in a temperature and humidity-controlled laboratory.

Pathophysiology and treatment of menopausal hot flashes.

Hot flashes are the most common symptom of menopause. Although the appearance of hot flashes coincides with estrogen withdrawal, this does not entirely explain the phenomenon because estrogen levels do not differ between symptomatic and asymptomatic women. Luteinizing throughout? hormone pulses do not produce hot flashes nor do changes in endogenous opiates.

Effects of symptomatic status and the menstrual cycle on hot flash-related thermoregulatory parameters.

Objective: To compare core body temperature variation, sweating thresholds, and sweat rate in symptomatic and asymptomatic postmenopausal women and in eumenorrheic women in the follicular and luteal phases.

Design: Twelve symptomatic and 10 asymptomatic postmenopausal women and 12 eumenorrheic women were recorded in a temperature- and humidity-controlled laboratory during thermoneutral and warm conditions. Core body temperature variation was measured with an ingested radiotelemetry pill, basal body temperature with a rectal thermistor, skin temperature with four skin surface thermistors, and sweat rate with a capacitance hygrometer.

Hot flashes, core body temperature, and metabolic parameters in breast cancer survivors.

Objective: To examine core body temperature, energy expenditure, and respiratory quotient among breast cancer survivors experiencing hot flashes and compare these data to published studies from healthy women.

Design: In an observational study, nine breast cancer survivors with daily hot flashes who met specified criteria spent 24 hours in a temperature- and humidity-controlled whole-room indirect calorimeter (ie, metabolic room). Demographic and disease/treatment information were obtained and the following were measured: hot flashes via sternal skin conductance monitoring (sampled every second); core body temperature via an ingested radiotelemetry pill (sampled every 10 seconds); and energy expenditure and respiratory quotient via a whole-room indirect calorimeter (calculated every minute).

Lack of sleep disturbance from menopausal hot flashes.

Objective: To determine whether hot flashes produce disordered sleep in symptomatic postmenopausal women.

Design: Controlled laboratory study.

Setting: Healthy volunteers in a university medical center.

Increased tyrosine phosphorylation mediates the cooling-induced contraction and increased vascular reactivity of Raynaud's disease.

Objective: Increased levels of protein tyrosine kinase (PTK) are mechanistically associated with increased contractile responsiveness to cooling. This study tests the hypothesis that increased PTK activity mediates the increased vascular reactivity to agonists and cooling associated with primary Raynaud's disease (RD).

Methods: The response of dermal arterioles isolated from control (n = 29) and RD (n = 29) subjects to contractile and dilatory agents at 37 degrees C and 31 degrees C was characterized using the microvessel perfusion technique.

Core body temperature variation in symptomatic and asymptomatic postmenopausal women: brief report.

Objective: To determine if core body temperature (T) fluctuations occur in asymptomatic as well as symptomatic postmenopausal women.

Design: Tc was recorded with an ingested radiotelemetry pill in symptomatic postmenopausal women who had a hot flash in the laboratory, in symptomatic women who did not have a hot flash in the laboratory, and in asymptomatic postmenopausal women.

Results: There were no significant differences in mean Tc or Tc variation, as measured by the standard deviation, among the three groups.