Abstract P337: Adolescent Sleep is Associated With Physical Activity and Sedentary Behavior Patterns

Abstract

Introduction: A decrease in sleep quantity and quality is a growing concern in the adolescent population. Concurrently, an increase in physical inactivity has been shown to be related to numerous health consequences. There is a lack of literature on the relationship between sleep, physical activity (PA) and sedentary behavior (SB) in the adolescent population, particularly looking at night-to-night sleep irregularity. Hypothesis: We hypothesized that increased PA and decreased SB in both objective and subject modalities would be associated with greater habitual sleep duration (HSD) and lesser habitual sleep variability (HSV) in this adolescent population. Methods: Objective and subjective sleep and activity measurements were collected from 295 adolescents in the Penn State Child Cohort follow-up examination. Objectively-measured variables were obtained through 7 consecutive days of actigraphy collection. HSD was calculated as the average sleep duration across 7 nights, and HSV was calculated as the standard deviation (SD) of intra-individual sleep duration. Subjects with <5 nights of sleep data were excluded from analysis. Self-administered questionnaires were used to collect subjectively-measured sleep, PA, and SB data. The relationships between sleep and behavior measures were assessed using linear regressions. All models were adjusted for age, sex, race and BMI percentile. Results: On average, our sample was 16.8 years, 52% male, and 79% white. We found that higher SB was associated with shorter HSD. With one SD change in objectively-measured SB (1014 minutes), HSD is reduced by 16 (3.6) minutes (p<0.05). Although not statistically significant, subjective SB showed a similar pattern. Unexpectedly, both objective and subjective measures of increased PA were associated with shorter HSD. In terms of HSV, we found that higher subjective SB was associated with greater HSV; specifically, with one SD change in subjectively-measured SB (8.64 points), HSV increased by 0.011 (0.004) minutes. None of the PA measures were significantly associated with HSV. Conclusions: In conclusion, objectively-measured sleep patterns are related to physical activity/inactivity. Our results emphasize the need of future studies to systematically assess the inter-relationship of sleep and physical activity in this population.