0191 Psychomotor Vigilance and Sleep Across the Menstrual Cycle

Abstract Introduction Sleep and cognitive performance have been shown to fluctuate across the menstrual cycle, but findings to date have been largely inconsistent and often compare menstrual phases between individuals, rather than measuring intraindividual differences. To address this gap, we tracked sleep and psychomotor vigilance throughout one complete menstrual cycle. Methods Eighteen premenopausal females (ages 18-36) with natural menstrual cycles tracked their sleep at home using actigraphy and daily sleep diaries. Individuals were asked to complete a maximum of 5 psychomotor vigilance tasks (PVT) per day (9am, 12pm, 3pm, 6pm, 9pm). PVT reaction time, total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), and self-reported sleep quality (SQ) were z-scored for each person across the menstrual cycle. K-means clustering was used on mean-level summary metrics (including PVT amplitude, highest and lowest reaction time days, and sleep parameters), and cluster differences evaluated using mixed effects models with participant as a random effect. Results PVT performance varied significantly across the menstrual cycle, with substantial variability between-participants. Three clusters were identified: cluster 1 showed slower PVT reaction time during the follicular phase, cluster 2 showed slower PVT reaction time mid-cycle, and cluster 3 showed slower PVT reaction time during the luteal phase. Mixed effects models were used to determine the interaction between sleep variables and PVT performance. Better SQ predicted faster PVT reaction times across participants (β = -0.17, p =0.031). However, this did not vary between clusters. Longer SOL was significantly associated with PVT reaction time for cluster 1 (β = +0.261, p < 0.001), but not for clusters 2 or 3. Conclusion These data suggest that there may be no one-size-fits-all relationship between menstrual phase, psychomotor vigilance, and sleep. Rather, there may be distinct phenotypes that give rise to phase-specific cognitive performance that varies between individuals. Further work is required to comprehensively measure cognition, sleep, and hormone status in a larger sample of premenopausal females. Support (if any)