Core body temperature and circadian rhythm of hot flashes in menopausal women.

Freedman, Robert R.; Norton, D.; Woodward, Suzanne; Cornélissen, Germaine

doi:10.1210/jcem.80.8.7629229

Cited by 92 publications

(68 citation statements)

References 16 publications

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“…We did not observe an increase in time spent in stage N1, but there may not have been enough objective hot flashes per night to detect a change in N1. Alternatively, the transient increase in core body temperature of up to 0.1°C that usually precedes each flash may also induce an awakening, [19][20][21] as has been observed in other clinical settings. 22 However, it is also plausible that N1 sleep and brief awakenings are more closely linked with hot flashes because neural factors that drive wakefulness also increase susceptibility to hot flashes, which are similarly triggered by cortical activation.…”

Section: Discussionmentioning

confidence: 92%

Nocturnal Hot Flashes: Relationship to Objective Awakenings and Sleep Stage Transitions

Bianchi

Kim

Galvan

et al. 2016

Journal of Clinical Sleep Medicine

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Study Objectives: While women report sleep interruption secondary to nighttime hot flashes, the sleep disrupting impact of nocturnal hot flashes (HF) is not well characterized. We utilized a model of induced HF to investigate the relationship of nighttime HF to sleep architecture and sleep-stage transitions. Methods: Twenty-eight healthy, premenopausal volunteers received the depot gonadotropin-releasing hormone agonist (GnRHa) leuprolide to rapidly induce menopause, manifesting with HF. Sleep disruption was measured on 2 polysomnograms conducted before and after 4-5 weeks on leuprolide, when HF had developed. Results: 165 HF episodes were recorded objectively during 48 sleep studies (mean 3.4 HF/night). After standardizing to sleep-stage time distribution, the majority of HF were recorded during wake (51.0%) and stage N1 (18.8%). Sixty-six percent of HF occurred within 5 minutes of an awakening, with 80% occurring just before or during the awakening. Objective HF were not associated with sleep disruption as measured by increased transitions to wake or N1, but self-reported nocturnal HF correlated with an increase from pre-to post-leuprolide in the rate of transitions to wake (p = 0.01), and to N1 (p = 0.008). Conclusions: By isolating the effect of HF on sleep in women without the confound of age-related sleep changes associated with natural menopause, this experimental model shows that HF arise most commonly during N1 and wake, typically preceding or occurring simultaneously with wake episodes. I NTRO DUCTI O NDuring midlife, sleep disturbance and insomnia increase significantly in women, with those who are perimenopausal and experiencing hot flashes most likely to develop such sleep problems. Hot flashes reduce perceived sleep quality by awakening women repeatedly throughout the night. Studies in midlife women have shown that nocturnal hot flashes were most likely to occur during stage N2 sleep and are commonly linked with an awakening.1-3 The link between nocturnal hot flashes and awakenings has raised the question of whether hot flashes directly induce awakenings. Evidence supporting this explanation includes data from peri-and postmenopausal women showing that 54% to 69% of objectively measured nighttime hot flashes are associated with an awakening.1-3 Among those hot flashes occurring proximate to an awakening, the specific temporal sequence between the onset of the awakening and the flash beginning varies, with studies showing that objectively measured nighttime hot flashes precede or begin simultaneously with the awakening 54% to 90% of time.1-3 The observation that a hot flash can begin after the onset of the awakening in some hot flash/wake episode pairs, particularly during the second half of the night, 3 raises the possibility that hot flashes do not uniformly induce awakenings, 2 even when they are temporally linked. Using controlled experimental studies, we established that new-onset hot flashes disrupt sleep by increasing the amount of wake time after sleep onset (WASO) and the number of awakeni...

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Section: Discussionmentioning

confidence: 92%

Nocturnal Hot Flashes: Relationship to Objective Awakenings and Sleep Stage Transitions

Bianchi

Kim

Galvan

et al. 2016

Journal of Clinical Sleep Medicine

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“…Venous blood-samples were taken for analysis of Testosterone (T), Follitropin (FSH), Lutropin (LH), Sex Hormone Binding Globulin (SHBG), albumin and capillary haemoglobin (Hb) and Bio-available Testosterone (BT) was calculated [20].…”

Section: Methodsmentioning

confidence: 99%

Hot flushes in healthy aging men differ from those in men with prostate cancer and in menopausal women

Holm

Thorell

Theodorsson

et al. 2011

Gynecological Endocrinology

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Abstract:Calcitonin Gene-Related Peptide (CGRP) seems to be involved in hot flushes in women and in castrated men. Therefore, we studied whether the plasma concentrations of CGRP changed during flushes in a group of healthy aging men. Twelve men (49-71 years) with no history of current or former prostate cancer or hormonal treatment reporting ≥20 flushes/week were investigated. Blood samples were drawn during and between flushes for analysis of CGRP and also androgen concentrations, i.e. Testosterone and Bioavailable Testosterone were analysed.Skin temperature and skin conductance were monitored.

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“…Studies by Freedman et al, using an ultrasensitive temperature probe, suggest that hot flushes are triggered by small elevations in core body temperature (Tc) acting within a narrowed thermoneutral zone in symptomatic postmenopausal women (3). This group found that small but significant elevations in Tc precede most (76%) hot flush episodes (3)(4)(5).…”

Section: Introductionmentioning

confidence: 99%

“…This group found that small but significant elevations in Tc precede most (76%) hot flush episodes (3)(4)(5). These same investigators subsequently found that postmenopausal women with hot flushes had a narrower thermoregulatory zone (0°C) compared with postmenopausal women who do not flush (0.4°C).…”

Section: Introductionmentioning

confidence: 99%