0697 IRREGULAR SLEEP SCHEDULE ASSOCIATES WITH DISTURBANCES OF MOOD AND MULTISCALE BEHAVIORAL REGULATION IN COLLEGE STUDENTS

Abstract

One of the major concerns regarding the lifestyle of college students is irregular sleep-wake cycles that may have adverse health consequences. The goal of this study was to test whether irregular sleep-wake schedules in college students associate with mood decline and perturbed motor activity regulation at multiple time scales. Forty-four healthy college students (18–30 years old) were studied for 3 weeks during their normal daily routines. Sleep-wake regularity (SWR) was determined based on daily sleep-wake diaries, and depression symptoms were assessed weekly based on the Beck Depression Index (BDI) questionnaire. Motor activity was continuously monitored using a wristband (Actiwatch or LKK ECG-Activity Monitor) throughout the 3 weeks, and data were stored over 1-min bins. To assess motor activity regulation, we calculated interdaily stability (IS) of daily activity rhythms and examined temporal correlations in activity fluctuations during wakefulness at multiple time scales from ~0.1–8 hours. Additionally, mean physical activity levels were assessed weekly based on International Physical Activity Questionnaires. College students with lower SWR had lower IS (p=0.0001) and higher BDI scores (p=0.0003). These associations were independent of physical activity levels. Additionally, for those students with physical activity levels <3345 METs (median of weekly values of all students), lower SWR was associated with more random activity patterns during wakefulness at time scales <1.5h (i.e., reduced temporal correlations, p=0.0077). No associations were observed for activity correlations at larger time scales. There was not enough power to determine the association between SWR and activity correlations in students with high physical activity levels because all these subjects had relatively higher SWR. Irregular sleep-wake schedules are associated with increased depression symptoms, less stable daily rhythms, and more random activity patterns during wakefulness in college students. NIH grants R00HL102241, R01AG048108, and P01AG00975; the International Postdoctoral Exchanging Fellowship 20150042 from China Postdoctoral Council.