157 The Circadian Variation of Sleep in Postmenopausal Women
Bibliographic record
Abstract
Abstract Introduction During menopause, 40-60% of women report sleep complaints. Despite the fact that menopause is associated with fluctuations in sex hormones that can affect circadian physiology, the role of circadian factors in sleep disturbances after menopause is not well understood. The present study aims to understand the circadian variation of sleep occurring after menopause. Methods Eight healthy postmenopausal women (PMW; 54.8±3.4 years, one taking hormones) without sleep complaints were enrolled and compared to previously-collected data from 12 healthy young women (YW; 25.8±3.4 years) in mid-follicular phase. Following an 8-h baseline sleep period aligned to their habitual sleep times, participants underwent a 48-h (PMW) or 72-h (YW) ultradian sleep-wake cycle procedure (USW) with 60-min wake episodes alternating with 60-min nap opportunities. Sleep was recorded with polysomnography. Circadian parameters (amplitude, phase) of core body temperature (CBT) and sleep were assessed and compared using mixed-effects linear models on the first 48 hours of USW. Sleep parameters, including total sleep time (TST), arousals, sleep onset latency (SOL), stages N1, N2, N3, REM, and wake, were compared between groups during baseline and USW. Results PMW presented earlier habitual bedtimes (23:07±00:11 vs 00:13±00:12) and rise-times (07:07±00:11 vs 08:13±00:12) compared to YW (p=0.005). There were no differences in amplitude, phase, or phase angle of CBT. An advanced acrophase of REM sleep (p=0.034) and lower amplitudes of TST, arousals, SOL, N3, and wake, were observed in PMW vs YW (p≤0.05). During baseline, PMW presented more stage N1 (p=0.030) and arousals (p<0.001) than YW. During USW, group effects were observed, with more stage N1 (p=0.007) and N2 (p=0.0007) in PMW vs YW. Significant interactions showed greater TST (p=0.009), shorter SOL (p=0.001), and more arousals (p=0.027) in PMW during the habitual day. Conclusion The primary finding in this small group of PMW with no sleep complaints was a general increase in light sleep and arousals across circadian phases. No differences in CBT rhythms were observed, whereas small differences in the circadian variation of TST, N3, and REM sleep were observed. Further studies are needed to clarify the role of circadian processes on sleep in PMW. Support (if any) Study supported by the Canadian Institutes of Health Research.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".