Magnitude of the impact of hot flashes on sleep in perimenopausal women

Abstract

Objective To quantify the impact of objectively-recorded hot flashes on objective sleep in perimenopausal women. Design Cross-sectional study. Participants underwent 1–5 laboratory-based polysomnographic recordings for a total of 63 nights, including sternal skin conductance measures, from which 222 hot flashes were identified according to established criteria. Data were analyzed with hierarchical mixed-effect models and Spearman correlations. Setting Sleep laboratory. Patients 34 perimenopausal women (Age±SD:50.4±2.7y). Intervention None. Main Outcome Measures Perceived and polysomnographic sleep measures (sleep quality, amount of wake after sleep onset and number of awakenings). Subjective (frequency and bother) and objective (frequency and amount of hot flash-associated wake time) hot flash measures. Results Women had an average of 3.5 (95%CI:2.8–4.2, range=1– 9) objective hot flashes per night. 69.4% of hot flashes were associated with an awakening. Hot flash-associated wake time per night was, on average, 16.6 min (95%CI:10.8–22.4), which accounted for 27.2% (SD 27.1) of total wakefulness per night. Hot flash-associated wake, but not frequency, was negatively associated with sleep efficiency and positively associated with wake after sleep onset. Also, self-reported wakefulness correlated with hot flash-associated wake, suggesting that women’s estimates of wakefulness are influenced by the amount of time spent awake in association with hot flashes during the night. More perceived and bothersome hot flashes correlated with more perceived wakefulness and awakenings and more objective hot flash-associated wake time and hot flash frequency. Conclusions The presence of physiological hot flashes accounts for a significant proportion of total objective wakefulness during the night in perimenopausal women.

Menstrual Cycle-Related Variation in Physiological Sleep in Women in the Early Menopausal Transition

“…We evaluated sleep spindle characteristics in addition to EEG activity and could show clear increases in spindle density and spindle duration in the luteal phase. We also measured hot flashes because hot flashes are known to disturb sleep (40,41). In this sample of early-transition women, few women had hot flashes; these events are likely to disrupt sleep more in late transition and early postmenopausal women.…”

Sleep During Menopausal Transition: A 6-Year Follow-Up

“…13 Poor sleep is reported especially in the presence of vasomotor symptoms. 2,4,14,15 Nevertheless, even today the researchers are not unanimous about the primary cause of menopausal sleep disturbance. In addition to fluctuations and decrease in reproductive hormone concentrations, aging itself, 16 depressive symptoms, 17,18 sleep-disordered breathing, primary sleep disorders, other systemic diseases and/ or their medications as well as psychosocial or behavioral factors may contribute to sleep impairment.…”

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

“…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][2][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.…”

“…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][2][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][2][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 the possibility that hot flashes do not uniformly induce awakenings, 2 even when they are temporally linked.…”

“…[1][2][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][2][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 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 awakenings measured objectively with polysomnography (PSG) proportionate to the number of nighttime hot flashes reported in the morning upon awakening.…”