0198 Effects of a 1-hour nightly weeklong sleep extension pilot study in undergraduates on health

Abstract

Abstract Introduction Sleep restriction impairs health, but less is known about the potential health benefits of extending sleep in undergraduate students with habitual short sleep. This study examined the effects of a 1-week, 1-hour per night sleep extension on cardiometabolic health, hydration status, sedentary behavior, and physical activity in undergraduate students. Methods Twelve healthy undergraduate students (83% female; mean±SD age 20.2±1.5; range 18-23 years) obtaining fewer than 7 hours of average nightly sleep completed a two-week study. The first week consisted of sleeping typically ("Habitual"), followed by a peer-delivered intervention to extend time in bed by ≥1 hour/night during the second week ("Extension"). Sleep and physical activity actigraphy were collected throughout. Following each week, participants completed in-person cardiometabolic assessments, including a standardized meal response procedure and blood pressure measurement. Blood samples for measurement of glucose and insulin were collected before, during, and following a standardized breakfast. Urine samples yielded markers of hydration (specific gravity and osmolality). Mixed-effects regression models with random intercepts for individuals compared outcomes after the Extension week to Habitual outcomes. Results Compared to Habitual sleep, average sleep duration across the Extension week increased (b±SEM, +42.6±.3 minutes; p=.005). After the breakfast meal, glucose area under the curve (AUC; −26.5±10.2 mg/dL*h; p=.025) and time to return to baseline levels (−83.0±46.4 minutes; p=.031) decreased following Extension. There was no change in insulin AUC. Systolic blood pressure decreased (−6.6±2.8 mmHg; p=.037) after Extension. Average time spent in sedentary behavior (−44.3±15.7 minutes; p=.018) and percentage of wake spent in moderate-to-vigorous physical activity (−1%±.4%; p=.030) decreased across the Extension week. Participants who increased average sleep duration ≥15 minutes (n=9) were better hydrated according to urine osmolality (−187.0±68.4 mOsm/kg; p=.026) and specific gravity (−.01±.002 g/mL; p=.012) and had lowered odds of dehydration according to urine osmolality (≥800 mOsm/kg; −67%; OR=.03; p=.035). Conclusion This pilot study provided evidence that sleep extension may improve cardiometabolic health and hydration and reduce both sedentary behavior and moderate-to-vigorous physical activity. Future research in randomized controlled trials should examine if such findings extrapolate to larger samples and older populations. Support (if any) CRC/CTSI: UL1-TR002014; pilot grant to AMC from the Department of Biobehavioral Health, Pennsylvania State University