title: Longitudinal Relationship between Cardiorespiratory Fitness and Academic Achievement.
abstract: OBJECTIVE
  The aim of this study was to examine the prospective associations between cardiorespiratory fitness (CRF) and academic achievement in the youth.
  
  
  METHODS
  The sample included 1286 fifth-, sixth-, and seventh-grade students, age 11 to 14 yr (Mage = 11.3 ± 1.1), from 14 schools followed for 3 yr. Academic achievement was assessed using the students' marks at baseline and at follow-up 3 yr apart, in Portuguese, mathematics, foreign language (English), and science. CRF was assessed by the Progressive Aerobic Cardiovascular Endurance Run test from the Fitnessgram battery. Students were classified as fit-fit, unfit-fit, fit-unfit, and unfit-unfit according to the Progressive Aerobic Cardiovascular Endurance Run test results at baseline and follow-up. Ordinal regression analyses were performed to examine associations between CRF and academic achievement.
  
  
  RESULTS
  Being persistently fit (fit-fit), compared with those classified unfit-unfit, increased the odds of having high levels of academic achievement in Portuguese (odds ratio (OR) = 3.49; 95% CI, 1.97-6.20; P < 0.001) and foreign language (OR = 2.41; 95% CI, 1.39-4.14; P < 0.01) at follow-up. Students that improved their CRF and became fit (unfit-fit) had also higher odds of achieving better marks than those persistently unfit-unfit in Portuguese (OR = 2.52; 95% CI, 1.42-4.45; P < 0.01) and foreign language (OR = 2.13; 95% CI, 1.23-3.67; P < 0.01).
  
  
  CONCLUSIONS
  Consistently high and improvements in cardiorespiratory fitness are prospectively associated with better academic achievement especially in mother tongue and foreign language.
authors.affiliation: 1Interdisciplinary Centre for the Study of Human Performance, Faculty of Human Kinetics, University of Lisbon, PORTUGAL; 2Environmental Health Institute, Lisbon Medical School, University of Lisbon, PORTUGAL; 3Faculty of Physical Education and Sport, Lusophone University of Humanities and Technologies, PORTUGAL; 4Department of Sport, European University, PORTUGAL; 5Department of Sport Medicine, Norwegian School of Sport Sciences, NORWAY; and 6MRC Epidemiology Unit, University of Cambridge, England, UNITED KINGDOM.
authors.forename: Luís B
authors.initials: LB
authors.lastname: Sardinha
authors.forename: Adilson
authors.initials: A
authors.lastname: Marques
authors.forename: Claudia
authors.initials: C
authors.lastname: Minderico
authors.forename: António
authors.initials: A
authors.lastname: Palmeira
authors.forename: Sandra
authors.initials: S
authors.lastname: Martins
authors.forename: Diana A
authors.initials: DA
authors.lastname: Santos
authors.forename: Ulf
authors.initials: U
authors.lastname: Ekelund
mesh_terms: D000124:Achievement; D000293:Adolescent; D000072599:Cardiorespiratory Fitness; D002648:Child; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D011174:Portugal; D013334:Students