Physical activity, fitness, weight status, and cognitive performance in adolescents.

OBJECTIVE: To examine the association of participation in physical sports activity during leisure time, sedentary behaviors, cardiorespiratory and muscular fitness, and weight status with cognitive performance in Spanish adolescents. STUDY DESIGN: This cross-sectional study comprised a total of 1820 adolescents (958 female) aged 13.0 to 18.5 years. Cognitive performance (verbal, numeric and reasoning abilities, and an overall score) was measured with the "SRA-Test of Educational Ability." Participation in physical sports activity during leisure time (yes/no) and time devoted to study, television viewing, and playing video games were self-reported and categorized as ≤ 3 hours/day and >3 hours/day. We assessed cardiorespiratory and muscular fitness with field-based tests. Adolescents were classified as underweight, normal weight, overweight, and obese. RESULTS: Participation in physical sports activities during leisure time was associated with better cognitive performance study variables (all P < .001), independent of potential confounders including cardiorespiratory fitness and body mass index. We did not observe an association of time devoted to study, television viewing, or playing video-games with cognitive performance. Likewise, cognitive performance was similar across cardiorespiratory and muscular fitness levels and body weight categories. CONCLUSION: Participation in physical sports activity during leisure time may positively influence cognitive performance in adolescents.

Associations between physical activity, fitness, and academic achievement.

OBJECTIVES: To explore the associations between objectively assessed intensity levels of physical activity and academic achievement and test whether cardiovascular fitness mediates the association between physical activity and academic achievement. STUDY DESIGN: Cross-sectional data were gathered in Swedish 9th-grade students (n = 232; mean age = 16 years; 52% girls). School grades, pubertal phase, skinfold thickness, cardiovascular fitness, and physical activity were measured objectively. Mother's education, family structure, and parental monitoring were self-reported. Data were analyzed with linear regression analyses. RESULTS: After controlling for confounding factors, academic achievement was associated with vigorous physical activity in girls (beta = .30, P < .01; explained variance of the model 26%), which remained after inclusion of fitness (beta = .23, P < .05; explained variance 29%). The association was not mediated by fitness. In boys, academic achievement was associated with pubertal phase (beta = .25, P < .05). After inclusion of fitness, it was only associated with fitness (beta = .25, P < .05; explained variance of the model 30%). CONCLUSION: In girls, academic achievement was associated with vigorous physical activity and not mediated by fitness, whereas in boys only fitness was associated with academic achievement. Further studies are necessary to investigate the potential longitudinal effect of vigorous physical activity on academic achievement, the role of fitness herein and the implications of these findings for schools.