Abstract
BackgroundSedentary behaviour is a major risk factor for developing chronic diseases and is associated with low cardiorespiratory fitness in adults. It remains unclear how sedentary behaviour and different physical activity subcomponents are related to cardiorespiratory fitness in children. The purpose of this study was to assess how sedentary behaviour and different physical activity subcomponents are associated with 10–14 year-old schoolchildren's cardiorespiratory fitness.Methods135 schoolchildren (81 girls, 12±1 year) completed 7-day minute-by-minute habitual physical activity monitoring using triaxial accelerometers and undertook a maximal cardiorespiratory fitness test.ResultsAfter controlling for sex, age, ethnicity, socioeconomic status and total wear time, light physical activity (1.5–2.9 METs) was negatively associated (β = −.24, p<.01) and hard physical activity (≥9 METs) positively associated (β = .45, p<.001) with cardiorespiratory fitness. Vigorous and hard physical activity were associated with cardiorespiratory fitness for boys (F = 5.64, p<.01) whereas light, moderate and hard physical activity were associated with physical fitness for girls (F = 10.23, p<.001). No association was found between sedentary time and cardiorespiratory fitness (r = −.13, p>.05). Sedentary to active transitions revealed little variability between cardiorespiratory fitness tertiles.ConclusionsHard physical activity (≥9 METs) holds greater potential for cardiorespiratory fitness compared to physical activity of lower intensities. There was no relationship between sedentary behaviour and cardiorespiratory fitness. These findings suggest that, for children, advice should focus on higher intensity physical activity and not sedentary behaviour as a means to maintain or improve cardiorespiratory fitness. Future research should explore longitudinal relationships between hard physical activity, cardiorespiratory fitness and health parameters.
Highlights
Low cardiorespiratory fitness is an independent risk factor for cardiovascular disease, type 2 diabetes mellitus, and mortality in adults [1] and is unfavourably associated with cardiometabolic risk factors in children and adolescents [2,3]
Inverse relationships exist between cardiorespiratory fitness and clustered cardiovascular disease risk scores in European youths (n = 2845) [4] and U.S adolescents (n = 1247) [5]
Sample A subset of 135 HAPPY study participant’s baseline data (81 girls, 1261 year) were included in this study as they met the accelerometry inclusion criteria and completed the maximal cardiorespiratory fitness test to exhaustion. Primary aims of this school-based intervention study were to increase overall time spent in moderate-vigorous physical activity during school and leisure time, and improve cardiorespiratory fitness, physical health and psychosocial well-being in 10–14 year-old children
Summary
Low cardiorespiratory fitness is an independent risk factor for cardiovascular disease, type 2 diabetes mellitus, and mortality in adults [1] and is unfavourably associated with cardiometabolic risk factors in children and adolescents [2,3]. Sedentary behaviour is a major risk factor for developing chronic diseases and is associated with low cardiorespiratory fitness in adults. It remains unclear how sedentary behaviour and different physical activity subcomponents are related to cardiorespiratory fitness in children. The purpose of this study was to assess how sedentary behaviour and different physical activity subcomponents are associated with 10–14 year-old schoolchildren’s cardiorespiratory fitness
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