Sedentary Behavior and the health of adolescents

Abstract

In modern societies, adolescents spend about half of their waking hours with sedentary behavior (SB). Therefore, the current study aims at investigating the relationship between SB and adolescents' health. A cross-sectional sample of 1296 students (8(th) grade) from 29 schools in Schleswig-Holstein, Germany was surveyed. Mean age was 13.75 years (SD = 0.67), 47.0 % were female. To asses screen-based and non-screen-based SB, moderate to vigorous physical activity as well as further indicators of health behavior (tobacco and alcohol use, diet) a questionnaire was used. Anthropometric data and blood pressure at rest were assessed during a medical testing and cardiorespiratory fitness was assessed by the 20 m-Shuttle-Run-Test. The students spent almost 7 hours a day sedentary. Total SB was positively associated with behavior that is detrimental to health. These associations were detectable only for screen-based SB, not for non-screen-based SB. Cardiorespiratory fitness was associated negatively with total SB, screen-based as well as non-screen-based SB. Associations remained widely stable when moderate to vigorous physical activity was controlled for. There were almost no associations between SB and blood pressure. Total SB, but especially screen-based SB seems to be a health risk factor in adolescence independent of physical activity. Besides fostering physical activity, reduction of SB should be a core target behavior in prevention and health promotion.