0061 INFLUENCE OF SLEEP AND CIRCADIAN PREFERENCE ON EXERCISE AND SUBJECTIVE MOOD IN COLLEGE UNDERGRADUATES

Abstract

Introduction: College is a critical developmental time period for establishing long-term health behaviors, including appropriate sleep timing and duration and exercise habits. Understanding how these behaviors interact, and also how they may influence subjective mood, is vital to identifying potential modifiable behaviors that may improve health during adulthood. Methods: 247 undergraduates (85 females) participated in a monthlong protocol. Sleep timing was monitored for 30 days using actigraphy and an online sleep log. Participants completed a daily online questionnaire at night and in the morning to document exercise sessions, duration, and timing. During an overnight laboratory stay ({\textless}4 lux), circadian phase was determined using salivary dim-light melatonin onset (DLMO, 5 pg/ml threshold) and subjective mood was determined from hourly visual analog scales (Happy/Sad). Sleep variability was determined using a sleep regularity index (SRI) we developed and chronotype was determined using the Munich Chronotype Questionnaire (MCTQ). Pearson correlations were used to determine associations between sleep and circadian outcomes with exercise and mood. Results: The percentage of days that participants exercised one or more times was significantly associated with SRI, DLMO, sleep onset and offset, and chronotype (all correlations p{\textless}0.05), such that less exercise was associated with more variable and later timing of sleep onset and offset, DLMO, and chronotype. Earlier chronotype, sleep onset and offset, and less variable sleep timing (all p{\textless}0.05) were significantly associated with subjectively happier mood. Percentage of days that participants exercised one or more times was a non-significant trend (p=0.09) for subjectively happier mood. Conclusion: Our findings reveal that time spent exercising in college students is significantly associated with sleep and circadian timing. These factors are also associated with college students' subjective mood ratings. Further work is needed to identify whether modifying sleep, circadian, and exercise behaviors in college students can improve long-term mood.