0968 SEDENTARY ACTIVITY, NOT MODERATE-TO-VIGOROUS ACTIVITY, FILLS THE EXTRA TIME AWAKE WHEN ADOLESCENTS RESTRICT THEIR SLEEP

Abstract

Introduction: Most teens obtain less sleep than recommended, with potential negative cognitive and physical consequences. Short sleep leads to increased daytime fatigue, which might be expected to translate to less time spent in physical activity. However, prior research has yet to examine the causal impact of short sleep versus healthy sleep on the activity and sedentary behavior of teens. Methods: Thirty-nine teens aged 14-18 completed a 3-week homebased experimental sleep manipulation protocol that began with a sleep stabilization week, followed in a randomized, cross-over fashion by 5-night periods of short sleep (SS; 6.5 hours in bed) versus healthy sleep (HS; 9.5 hours in bed). Sleep was verified via wrist-mounted actigraphy. Physical activity during waking hours was measured via a waist-mounted accelerometer to derive average daily time spent in sedentary, light, and moderate-to-vigorous (MVPA) physical activity based on age-based cut points. Results: During the SS condition, teens slept 6.23 hours and during HS slept 8.61 hours (2.4 hour difference; p