J Youth Adolescence 2015 44 298 316 DOI 10 1007 s10964 014 0244 2 EMPIRICAL RESEARCH Daily Diary Reports of Social Connection Objective Sleep and the Cortisol Awakening Response During Adolescents First Year of College Michael R Sladek Leah D Doane Received 25 September 2014 Accepted 15 December 2014 Published online 24 December 2014 Springer Science Business Media New York 2014 Abstract Poor sleep and alterations in the stress sensitive hypothalamic pituitary adrenal HPA axis may be mechanisms through which loneliness impacts adolescents well being Few researchers have explored whether daily variation in experiences of social connection predict dayto day variation in sleep and HPA axis activity among adolescents navigating the college context Using daily diary reports of social connection objective measures of sleep actigraphy and naturalistic salivary assessment the present study examined within person associations between first year college students social connection during the day and sleep that night as well as diurnal cortisol activity the following day The present study also explored trait level loneliness as a moderator of these associations after adjusting for baseline loneliness assessed in high school Seventy one first year college students 23 male Mage 18 85 52 non Hispanic White completed daily diary reports wore a wrist based accelerometer actigraph watch and provided saliva samples five times daily across three consecutive weekdays The results from hierarchical linear models indicated that within person increases in daily social connection were significantly associated with longer time spent in bed and more actual time asleep that night only for adolescents high on loneliness Within person increases in daily social connection were associated with a greater cortisol awakening response CAR the next day regardless of trait loneliness These findings illustrate that more daily social M R Sladek L D Doane Department of Psychology Arizona State University P O Box 871104 Tempe AZ 85287 1104 USA e mail msladek asu edu L D Doane e mail Leah Doane asu edu 123 connection with others than usual may predict improved sleep quantity for lonely adolescents and a physiological index of anticipating upcoming daily demands CAR in general Future intervention programs might consider including strategies focused on enhancing daily social interactions among adolescents starting college particularly for lonely adolescents Keywords Social connection Loneliness Adolescents Sleep Cortisol Diary studies Transition to college Introduction Loneliness perceiving a lack of quality or quantity in social relationships is a risk factor for poor health Pedersen et al 2007 Waldrip et al 2008 and has specifically been linked to poor sleep Cacioppo et al 2002a and alterations in hypothalamic pituitary adrenal HPA axis activity Doane and Adam 2010 among adolescents Indeed changes in sleep and HPA axis activity may be mechanisms through which loneliness impacts health and well being as adolescents develop Cacioppo et al 2002b Hawkley and Cacioppo 2003 2010 Rao et al 2009 Despite a strong tradition of considering how social relationships and support from others contribute to resilience across development e g Holt Lunstad et al 2010 Hostinar et al 2014 Rao et al 2010 relatively few researchers have explored whether daily experiences of interacting and engaging with others might be associated more directly with day to day changes in key biological mechanisms linked with adolescents health sleep and physiological stress activity Even fewer researchers have explored such questions using daily diary reports of social connection in combination with objective measures of sleep and cortisol J Youth Adolescence 2015 44 298 316 activity among adolescents who have entered the college environment Based on prior theoretical and empirical work highlighting loneliness during adolescence and the college years e g Hawkley et al 2007 Laursen and Hartl 2013 the daily impact of social connection on these health markers is likely to differ based on individual differences in loneliness among adolescents adapting to the new social context of college Implementing this research in naturalistic settings is critical and has the potential to directly inform intervention programs by identifying how fluctuations in social connection contribute to adolescents health on a day to day basis potentially in different ways for different adolescents as they begin their first year of college To address limitations of available studies we utilized a modified ecological momentary assessment EMA protocol Stone and Shiffman 1994 in a longitudinal sample of adolescents transitioning to college to examine sleep an important health behavior and diurnal cortisol activity including several indices of daily stress physiology In addition to demonstrated links with social connection or lack thereof both sleep and diurnal cortisol activity can be measured reliably in adolescents naturalistic settings e g Zeiders et al 2011 These outcomes represent different although often related regulatory processes that maintain homeostasis in the body Steiger 2002 Sleep regulation reflects both circadian rhythmicity and adolescent behaviors i e choices that adolescents make regarding their sleep schedule whereas cortisol is a much more specific marker of HPA axis stress physiology We used daily diary reports actigraphic sleep and naturalistic salivary collection to examine whether intra individual variation in social connection during the day was associated with objective measures of sleep duration and quality as well as with diurnal cortisol patterns the following day Taking advantage of a longitudinal study design we also explored whether changes in loneliness from senior year of high school to the first year of college moderated these associations We were particularly interested in investigating whether days characterized by greater social connection than usual i e within person increases would be associated with improved sleep and alterations in the cortisol awakening response CAR the next day for adolescents who struggled with increasing loneliness after transitioning to college Social and Developmental Context Adolescents Who Transition to College Social support from friends becomes increasingly important for social emotional growth and adjustment during adolescence Parker et al 2006 Rubin et al 2006 By the time they reach high school adolescents spend less time