Impact of sleep fragmentation on perceived sleep quality and daytime sleepiness in an experimental model of menopausal sleep fragmentation with normative sleep duration

The menopausal transition is associated with greater difficulty maintaining sleep and poor subjective sleep quality. We evaluated the impact of objectively measured changes in sleep and estradiol withdrawal on subjective sleep quality and daytime sleepiness.

Design

Twenty-three healthy premenopausal women completed 5-night inpatient studies during the mid/late follicular phase of the menstrual cycle [mean (±SE) serum estradiol 81.3±12.2 pg/ml]. A subset (n=17) completed the same 5-night inpatient study under a hypo-estrogenic state following leuprolide administration (serum estradiol 7.8±1.7 pg/ml). Each inpatient study was comprised of 2 nights of 8-h undisturbed time in bed (TIB) followed by 3 nights of 9-h TIB that included ~1 h of experimentally induced wake after sleep onset (WASO), while allowing up to ~8 h of total sleep time (TST). Sleep was assessed by polysomnography (PSG), first-morning subjective sleep quality on a scale (range 1-7, lower score worse), and sleepiness on the self-rated Karolinska Sleepiness Scale (KSS). Associations were tested using repeated measures linear mixed models; correlation strengths were estimated with Pearson’s r.

Results

Worse subjective sleep quality correlated with more WASO (r=-0.46, p<0.01), more N1 sleep (r=-0.34, p<0.01), less N3 sleep (r=0.34, p<0.01) but only weakly with TST (r=0.1, p=0.03). More subjective daytime sleepiness (KSS) correlated with more WASO (r=0.25, p<0.01) but not with TST (r=0.07, p=0.76). Estradiol withdrawal did not affect WASO or TST (both p≥0.28) and was not associated with subjective sleep quality or sleepiness (both p≥0.74).

Conclusions

More WASO distributed across the sleep episode correlated with poorer subjective sleep quality and increased daytime sleepiness even when TST was maintained within the recommended range. These results have important implications for understanding the impact of menopausal sleep fragmentation on perceived sleep quality and daytime sleepiness even when women meet the recommended guidelines for sleep duration.

Support. NIH-NIA R01AG053838.