The Mediation of the Relationship between Social Rhythmicity and Sleep by Light, Arousal, and Affect in Both Younger and Older Adults

by Natalie Dautovich

Institution: University of Florida
Department: Counseling Psychology, Psychology
Year: 2010
Keywords: adults, affect, arousal, elderly, geriatric, intraindividual, light, older, rhythmicity, sleep, social, younger; Psychology
Record ID: 1868031
Full text PDF: http://ufdc.ufl.edu/UFE0021116


Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy THE MEDIATION OF THE RELATIONSHIP BETWEEN SOCIAL RHYTHMICTY AND SLEEP BY LIGHT, AROUSAL, AND AFFECT IN BOTH YOUNGER AND OLDER ADULTS By Natalie Deidre Dautovich August 2010 Chair: Christina McCrae Major: Counseling Psychology Light currently reigns as the dominant factor influencing human circadian rhythms such as sleep. Recently, interest has shifted to other external factors which may influence circadian systems. Social activities (e.g., meal times, timing of exercise) are thought to exert effects on the timing of circadian rhythms. Social activities may entrain circadian rhythms either directly or indirectly by influencing exposure to light. Little research, however, has investigated mechanisms other than light that underlie the relationship between the rhythms of social activities and sleep. The present study examined the role of arousal and affect, in addition to light, as potential mediators of the relationship between social rhythms and sleep. The overarching goals were to 1) examine the amount of variability within social rhythmicity, light, arousal, affect and sleep; 2) examine how variability in social rhythmicity, light, arousal, and affect is related to sleep; 3) examine the day-to-day and overall relationships between social rhythmicity, light, arousal, affect, and sleep; and 4) examine the mediation of the relationship of social rhythmicity and sleep by light, arousal, and affect. Each of these goals was investigated in both younger and older adults. Younger (n = 50) and older (n = 50) community-dwelling individuals were recruited from the North Central Florida area and online. Participants completed daily online diaries for 14 consecutive days. Social activities were assessed using the Social Rhythm Metric (SRM-17), light exposure was evaluated with the Light Exposure Scale (LES), arousal was assessed using the Affect Grid, the Pre-Sleep Arousal Scale (PSAS), and the UWIST Mood Adjective Checklist Revised (UMACL-R), affect was evaluated with the Affect Grid and the Positive and Negative Affect Scale (PANAS), and sleep was assessed using a sleep diary. Results indicated that younger adults were highly variable within person for all variables. Younger adults were significantly more variable on all measures than older adults except for the PSAS somatic scale. Despite showing less variability compared to younger adults, older adults still demonstrated considerable variability. Age-related differences in mean-levels were observed for social rhythmicity, light exposure, arousal, affect, and sleep. Variability in social rhythmicity, light, arousal, and affect was associated with worse sleep for younger adults and better and worse sleep for older adults. Multi-level modeling analyses showed that social rhythmicity predicted sleep at the between person level and light, arousal, and affect predicted sleep at both within and between person levels…