TY - JOUR
T1 - Is core temperature the trigger of a menopausal hot flush?
AU - Jones, Helen
AU - Bailey, Tom G.
AU - Barr, David A.
AU - France, Madeleine
AU - Lucas, Rebekah A.I.
AU - Crandall, Craig G.
AU - Low, David A.
N1 - Funding Information:
Received February 7, 2019; revised and accepted April 10, 2019. From the 1Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, England; 2Centre for Research on Exercise, Physical Activity and Health, School of Human Movement and Nutrition Sciences, The University of Queensland, Australia; 3School of Sport, Exercise and Rehabilitative Sciences, University of Birmingham, Birmingham, UK; and 4Department of Internal Medicine, University of Texas Southwestern and Texas Health Presbyterian Hospital Dallas, TX. Funding/support: Part of this project was supported by the NIH, National Institute on Aging (AG030189). Financial disclosure/conflicts of interest: None reported. Address correspondence to: Helen Jones, PhD, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool L3 3AF, UK. E-mail: h.jones1@ljmu.ac.uk
Publisher Copyright:
© 2019 by The North American Menopause Society.
PY - 2019/9/1
Y1 - 2019/9/1
N2 - Objective:Menopausal hot flushes negatively impact quality of life and may be a biomarker of cardiovascular and metabolic disease risk; therefore understanding the physiology of hot flushes is important. Current thinking is that a small elevation (∼0.03-0.05oC) in core temperature surpasses a sweating threshold (that is reduced in the menopause), sweating is activated, and a hot flush ensues. Nevertheless, more recent studies examining thermoregulatory control question whether core temperature per se can explain the trigger for a hot flush. The primary aim of this study was to assess the contribution of increases in core temperature on the occurrence of menopausal hot flushes.Methods:For this purpose, 108 hot flushes were objectively assessed in a laboratory setting in 72 symptomatic postmenopausal women (aged 45.8±5.1 years; body mass index 25.9±4.5kg/m2) from five previously reported studies. Women rested, wearing a tube-lined suit (or trousers), which was perfused with 34oC water. A subset then underwent mild heat stress (48°C water). Sweat rate, skin blood flow, blood pressure, heart rate, skin, and core temperature were measured continuously throughout. A hot flush was objectively identified during rest (spontaneous hot flush) or mild heating as an abrupt increase in sternal sweat rate. Further, a subset of symptomatic postmenopausal women (n=22) underwent whole-body passive heating for 60 minutes to identify core temperature thresholds and sensitivities for sweat rate and cutaneous vasodilation, which were compared to a subset of premenopausal women (n=18). Data were analyzed using t tests and/or general linear modeling, and are presented as mean (95% confidence interval).Results:In the 20 minutes before a spontaneous hot flush, core temperature increased by 0.03±0.12oC (P<0.05), but only 51% of hot flushes were preceded by an increase in core temperature. During mild heating, 76% of hot flushes were preceded by an increase in core temperature. The temperature thresholds for sweating were similar, but the vasodilatory threshold was higher in postmenopausal compared with premenopausal women (37.1±0.2 vs 36.8±0.3°C; P=0.06).Conclusion:We provide new evidence that menopausal hot flushes are unlikely triggered by an increase in core temperature. These findings provide important information about the physiology of hot flushes that have implications for treatment and management options for menopausal hot flushes.
AB - Objective:Menopausal hot flushes negatively impact quality of life and may be a biomarker of cardiovascular and metabolic disease risk; therefore understanding the physiology of hot flushes is important. Current thinking is that a small elevation (∼0.03-0.05oC) in core temperature surpasses a sweating threshold (that is reduced in the menopause), sweating is activated, and a hot flush ensues. Nevertheless, more recent studies examining thermoregulatory control question whether core temperature per se can explain the trigger for a hot flush. The primary aim of this study was to assess the contribution of increases in core temperature on the occurrence of menopausal hot flushes.Methods:For this purpose, 108 hot flushes were objectively assessed in a laboratory setting in 72 symptomatic postmenopausal women (aged 45.8±5.1 years; body mass index 25.9±4.5kg/m2) from five previously reported studies. Women rested, wearing a tube-lined suit (or trousers), which was perfused with 34oC water. A subset then underwent mild heat stress (48°C water). Sweat rate, skin blood flow, blood pressure, heart rate, skin, and core temperature were measured continuously throughout. A hot flush was objectively identified during rest (spontaneous hot flush) or mild heating as an abrupt increase in sternal sweat rate. Further, a subset of symptomatic postmenopausal women (n=22) underwent whole-body passive heating for 60 minutes to identify core temperature thresholds and sensitivities for sweat rate and cutaneous vasodilation, which were compared to a subset of premenopausal women (n=18). Data were analyzed using t tests and/or general linear modeling, and are presented as mean (95% confidence interval).Results:In the 20 minutes before a spontaneous hot flush, core temperature increased by 0.03±0.12oC (P<0.05), but only 51% of hot flushes were preceded by an increase in core temperature. During mild heating, 76% of hot flushes were preceded by an increase in core temperature. The temperature thresholds for sweating were similar, but the vasodilatory threshold was higher in postmenopausal compared with premenopausal women (37.1±0.2 vs 36.8±0.3°C; P=0.06).Conclusion:We provide new evidence that menopausal hot flushes are unlikely triggered by an increase in core temperature. These findings provide important information about the physiology of hot flushes that have implications for treatment and management options for menopausal hot flushes.
KW - Core temperature
KW - Hot flush
KW - Menopause
KW - Thermoregulation
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U2 - 10.1097/GME.0000000000001357
DO - 10.1097/GME.0000000000001357
M3 - Article
C2 - 31453964
AN - SCOPUS:85071458780
SN - 1072-3714
VL - 26
SP - 1016
EP - 1023
JO - Menopause
JF - Menopause
IS - 9
ER -