Subjective and objective measures of hot flashes

Abstract

Up to 75% of women in the US report having experienced hot flashes during the menopausal transition. The purpose of this review is to describe the physiology of hot flashes, and the ways in which hot flashes have been examined by subjective report and by objective measurement. Hot flashes occur because of an activation of the heat dissipation response, possibly triggered by a hypothalamic mechanism within the context of declining estrogen levels. There is cross-population variation in the frequency of self-reported hot flashes, although cross-study comparisons are problematic because of incompatibilities in study design. Diaries are a good way to collect information on the time and severity of hot flashes, and body diagrams allow researchers to study the pattern of heat and sweating. Hot flashes can be objectively measured by increases in heart rate, finger blood flow, respiratory exchange ratio, skin temperature, and core body temperature. Sternal skin conductance is the method most highly correlated with subjective hot flash report. In a laboratory, concordance between subjective report and sternal skin conductance can approach 100%. Ambulatory monitoring allows for the tracking of hot flashes during a woman's daily routine or sleep; however, concordance is much lower with ambulatory, compared to laboratory, monitoring. The study of hot flashes at menopause provides a model for the study of any experience that can be assessed by both self-report and biometric measurement.

Cortisol dysregulation is associated with daily diary‐reported hot flashes among midlife women

“…These findings contribute to the previously sparse empirical evidence linking hot flash severity and occurrence with cortisol dysregulation, supporting a relationship between alterations in HPA axis functioning and hot flashes that is independent of health factors, demographics and negative affect. The results of this study may suggest a role of HPA axis functioning and cortisol dysregulation in the aetiology of hot flashes, contributing to our limited understanding of how these common symptoms occur and variability in how they are perceived.…”

“…Despite these limitations, this study had considerable strengths. This study improves upon past methodological limitations including very small sample sizes, retrospectively reported hot flashes and limited cortisol collection . A particularly notable methodological advance of the present study is the use of electronic daily diaries for ambulatory assessment of hot flashes.…”

“…One recent study supports an association between a high frequency of moderate‐to‐severe hot flashes and some salivary cortisol abnormalities . Several other studies using small samples support an acute cortisol response to hot flashes among symptomatic women, with increases in serum cortisol concentration demonstrated shortly after a hot flash …”

Revisiting the Cutaneous Impact of Oral Hormone Replacement Therapy

“…For years, HRT effects on the skin have deservedly attracted interest [2, 24, 25, 28], but evidence-based issues remained unsettled or controversial [25, 29, 30]. It seems that short term HRT treatments fail to bring marked improvements on the skin structure [29, 30].…”

Hot flashes and midlife symptoms in relation to levels of salivary cortisol

“…Although it was possible to ask whether symptomatic women had higher levels of cortisol or a different diurnal pattern of cortisol rise and decline, a limitation of this study is that hot flashes were queried as having occurred during the past two weeks while cortisol levels were sampled over a 24-hour period. In addition, hot flashes were measured by subjective report rather than objective monitor (Carpenter et al 1999; Sievert 2013). Future work should examine cortisol levels on the same day in which women are asked to keep a diary and/or wear an ambulatory hot flash monitor (Rubin et al 2014).…”