title: Screen time impairs the relationship between physical fitness and academic attainment in children.
abstract: OBJECTIVE
  The purpose of this study was twofold: to analyze the association between physical fitness and academic attainment, and to determine the influence of screen time on the association between physical fitness and academic attainment.
  
  
  METHODS
  A cross-sectional study including 395 schoolchildren from seven schools of the Maule Region, Chile (mean age 12.1 years; 50.4% boys) participated in the autumn of 2014 (March to June). Self-reported physical activity and screen time were evaluated. The study measured academic achievement (mean of the grades obtained in several core subjects), physical fitness (cardiorespiratory fitness and muscular strength), weight, height, parental education, and socioeconomic status. Linear regression analysis was used to analyze the relationships between physical fitness and academic attainment after adjusting for potential confounders by gender. Analysis of variance was used to analyze the differences in academic attainment according to fitness and screen time categories (< 2 hours/day and ≥ 2 hours/day).
  
  
  RESULTS
  In both genders good cardiorespiratory fitness levels were associated with high language (β=0.272-0.153) and mean academic attainment (β=0.192-0.156) grades; however, after adjusting for screen time and other potential confounders, these associations disappear. Similarly, no relationship was observed after analyzing those children who spend more hours of screen time (≥ 2 hours/day).
  
  
  CONCLUSIONS
  Academic attainment is associated with higher cardiorespiratory fitness levels; however, it was weakly impaired by screen time. These findings seem to suggest that parents and policymakers should minimize the negative effects of screen time on children's lives to maximize the beneficial effect of healthy habits on academic attainment.
authors: Universidad Autónoma de Chile, Talca, Chile.
authors: Macarena M
authors: MM
authors: Aguilar
authors: Universidad Autónoma de Chile, Talca, Chile.
authors: Felipe A
authors: FA
authors: Vergara
authors: Universidad Autónoma de Chile, Talca, Chile.
authors: Erikson J A
authors: EJ
authors: Velásquez
authors: Universidad Autónoma de Chile, Santiago de Chile, Chile.
authors: Raquel
authors: R
authors: Marina
authors: Laboratorio de Ciencias de la Actividad Física, el Deporte y la Salud, Universidad de Santiago de Chile, USACH, Santiago de Chile, Chile. Electronic address: antoniogh@unex.es.
authors: Antonio
authors: A
authors: García-Hermoso
mesh_terms: D000124:Achievement; D015992:Body Mass Index; D002648:Child; D002677:Chile; D003430:Cross-Sectional Studies; D004521:Educational Measurement; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008838:Microcomputers / Q000706:statistics & numerical data*; D009043:Motor Activity / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D057185:Sedentary Behavior; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013690:Television / Q000706:statistics & numerical data*; D013997:Time Factors; D018910:Video Games / Q000009:adverse effects*
keywords: Academic performance; Aptidão cardiorrespiratória; Cardiorespiratory fitness; Desempenho acadêmico; Estilo de vida sedentário; Força muscular; Muscular strength; Sedentary lifestyle