1. Impact of School Start Time Changes on Sleep Patterns in Elementary through High School Age Students Background Science often plays an underrepresented role in school start-time decisions, even though research has indicated that adolescents biologically need approximately 9.25 hours a night, which is consistently not being met. Early school start times may exacerbate the challenge of adolescents obtaining the needed amount of sleep on weeknights. A rising trend of school leaders and the lay community have begun to consider implementing changes to their school schedule. While research has demonstrated that adolescents benefit from shifts to later school start times, little has been reported on how earlier start times affect elementary age students. Design/Methods Study Subjects Students in grades 3-5 (n=689) and grade 10 (n=190) completed a self- administered survey including questions on sleep duration in the spring of 2009 and again in 2010 (grades 3-5, n=625; grade 10, n=217). In Fall 2009, students in grades 3-5 switched from a start time of 8:20am to 7:45am and students in grades 6-12 switched from a start time of 7:30am to 8:15am. Sleep Questionnaires Questionnaires addressed sleep and wake times, sleepiness variables, and information regarding morning and evening routines. Statistical Analysis Descriptive statistics were used to quantify responses by grade. Conclusions Results indicate that the district-wide school start time change did not significantly decrease the total amount of sleep reported by either elementary or high school aged students. Heightened community awareness may account for why 3 rd graders reported longer sleep durations after the change, even when faced with earlier school start times. More than double the percentage of 10 th graders reported being able to awaken independently in the year following the change. Understanding the impact of school start times on sleep patterns will assist parents, health care providers and educators in promoting sleep hygiene in school-aged children and enable informed decision-making regarding start times. Objective To examine the effect of a district-wide change in school start times on sleep patterns in children and adolescents. Erica Appleman 1, Karina Stavitsky 2, Rhoda Au 3,4 1 Section of Endocrinology, Diabetes and Nutrition, Department of Medicine, Boston University School of Medicine & Boston Medical Center, 2 Department of Psychology, Boston University, 3 Framingham Heart Study, 4 Department of Neurology, Boston University School of Medicine GradeOld Wake Up Time (AM)New Wake Up Time (AM)Difference (Minutes) 36:496:57+8 46:566:22-34 56:596:23-36 106:206:53+33 GradeOld Bed Time (PM)New Bed Time (PM)Difference (Minutes) 38:378:22+15 48:528:22+30 59:108:43+27 1010:36 0 Grade Old Total Sleep Time (HH:MM) New Total Sleep Time (HH:MM)Difference (Minutes) 310:1110:35+24 410:039:59-4 59:499:40-9 107:428:17+35 Limitations Self-reported measures may be inherently biased. Community outcry necessitated that the data collection process involve no student identifying information, preventing direct longitudinal comparison. But over 90% of students from each grade in Spring 2009 attended the next grade in the same school system in Fall 2009. Thus, a large subset of students who took the initial survey comprised the student sample that took the second survey the following year.