Cardiorespiratory fitness (CRF) and physical activity (PA) appears associated with young people’s cognition (14,28). CRF is identified as a factor that might be related to cognitive control (3,21,23), brain plasticity (20), better cognitive abilities (4,18,22), and memory improvement (19,29). Thus, improving neurocognitive functions might result in better academic achievement, as has been demonstrated in several studies (5,11,33).
Although several studies have analyzed the relationship between CRF and academic achievement, most studies have been limited by cross-sectional designs (14,16,24,36). Results from these cross-sectional studies generally suggest a positive association between CRF and academic achievement, even when analyses were controlled for PA and for the linear and nonlinear relations between PA and CRF with academic achievement (16).
However, cross-sectional designs do not allow inferences of temporality or a possible causal relationship between CRF and academic achievement. A longitudinal design addresses the issue of directionality by allowing an examination of changes over time in CRF and the effect of these changes on academic achievement and allows stronger inference about causality. So far, few studies have examined the prospective associations between CRF and academic achievement (6,27,39). The results from these studies indicated that persistently cardiorespiratory fit students have better academic achievement than those who are persistently unfit (6,27,39). In contrast, others have failed to demonstrate associations between CRF with academic skills or academic achievement (15,29).
Additional large-scale studies are therefore needed to understand the impact of CRF on the current and future students’ academic achievement from different cultural settings to inform future interventions aimed at improving academic achievement in the youth. To the best of our knowledge, no previous study has investigated the influence of CRF on academic achievement in a comprehensive sample of students using a 3-yr prospective study design. Therefore, the aim of this study was to examine the prospective associations between CRF and academic achievement in the youth.
Study design and participants.
Participants were part of the Physical Activity and Family-Based Intervention in Paediatric Obesity Prevention in the School Settings (PESSOA project). This project was applied to students from 14 public schools, in the Oeiras Municipality, between 2009 and 2011. Detailed information about the PESSOA project is described elsewhere (32).
For the purpose of this study, only those children and adolescents who provided data on both CRF and academic grades at both baseline and follow-up were included (N = 1286). Participants were between 9 and 14 yr (M age = 11.3 ± 1.1) at baseline and between 12 and 17 yr (M age = 13.9 ± 1.2) 3 yr later at follow-up. Data were analyzed as a cohort analysis combining the intervention and control schools.
Participants were informed about the objectives of the study, and written informed consent was obtained from the legal guardians. The study received approval from the Scientific Committee of the Faculty of Human Kinetics at the University of Lisbon, the Portuguese Minister of Education, and the principals of each school surveyed. The study was conducted in accordance to ethical standards in sport exercise research (17).
Measures and procedures.
Academic achievement was assessed using students’ marks at the end of the academic year at baseline and at follow-up 3 yr later, in Portuguese (mother tongue), mathematics, foreign language (English), and science. Students’ marks in all subjects are based on the students’ performance throughout the year, considering the written exams (at least six in each discipline), oral class participation, and paper works. This is an assessment procedure very common in Portuguese schools. In Portuguese elementary school (from grade 5 to 9), students’ marks range from 1 to 5 (1 = very poor, 2 = poor, 3 = average, 4 = good, and 5 = very good). For data analysis in the current study, students were grouped into low (marks 1 and 2), average (mark 3), and high academic achievement (marks 4 and 5). Students’ marks were available from the administrative services of each school at the end of the academic years.
CRF was assessed by the Progressive Aerobic Cardiovascular Endurance Run (PACER) from the Fitnessgram test battery (8). The PACER is an incremental running test comprising a 20-m shuttle run with progressively less time to complete each shuttle. CRF was estimated as the number of stages completed. Participants were classified into fit and unfit according to the Fitnessgram cut points based on sex-and age-related criteria. The cut points are related to the minimum level of fitness that is assumed to prevent diseases from low fitness (8). Body weight was assessed to the nearest 0.1 kg wearing minimal clothes and without shoes, and height was measured to the nearest 0.1 cm. Body mass index (BMI) was calculated by the Quetelet index [weight (kg)/height (m)2]. CRF, weight, and height were collected during physical education classes within 1 wk at the end of each academic year. Fitness tests were administered by research trainees supervised by physical education teachers to ensure an accurate and reliable Fitnessgram administration.
The PESSOA project was originally a school-based obesity intervention. To test whether the intervention may modify the association between CRF and academic achievement, we modeled the interaction (school × CRF). No significant interactions were observed (P > 0.05) for any of the outcomes, and therefore, schools were combined with further adjustment for school (intervention and control). Descriptive statistics (means, SD, and percent) were used to characterize the sample. To capture changes in CRF over a 3-yr period, we examined children and adolescents’ CRF result trajectories stratified into four groups as follows: 1) fit at both baseline and follow-up (fit–fit); 2) unfit at the baseline and fit at the follow-up (unfit–fit); 3) fit at baseline and unfit at the follow-up (fit–unfit); and finally, 4) unfit at both baseline and follow-up (unfit–unfit). Bivariate relationships between academic achievement for each academic subject and CRF trajectory were tested by the χ 2. Several ordinal regressions were performed to analyze associations between CRF and academic achievement (low, average and high) at baseline, at follow-up, and through the trajectory (baseline × follow-up). Parameter estimates from these analyses were transformed into odds ratio (OR) of being at a higher level of academic achievement [exp(estimates)]. The OR was calculated using unfit at both time points as the reference. The analyses were adjusted for sex, BMI z-score, academic achievement at baseline, and school (interventions and control). Data analysis was performed using SPSS 22. For all tests, statistical significance was set at P < 0.05.
The sample characteristics and academic achievement at baseline and follow-up are presented in Table 1. The proportion of students categorized as high according to their grades in Portuguese, mathematics, foreign language, and science decreased over follow-up, and the proportion of students categorized as fit increased from baseline to follow-up.
Academic achievement according to the CRF trajectory is presented in Table 2. For mathematics (χ 2(6) = 16.51, P = 0.011) and foreign language (χ 2(6) = 15.81, P = 0.015), children and adolescents persistently fit (fit–fit) and those unfit at baseline and fit at follow-up (unfit–fit) had significantly better academic results at follow-up than those classified as unfit at both time points and those who deteriorated (fit–unfit) between baseline and follow-up.
Table 3 presents the results of the ordinal regression analyses. High CRF at baseline was related to higher levels of academic achievement at the follow-up only in Portuguese (OR = 1.65; 95% CI, 1.15–2.36; P < 0.01). Being categorized as consistently fit substantially increased the likelihood of having high levels of academic achievement in Portuguese (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) compared with those classified as consistently unfit. Those that were unfit at baseline and improved their CRF and became fit at follow-up had also higher odds of achieving better marks than those classified as consistently 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).
We examined the relationship between academic achievement and CRF among children and adolescents in a comprehensive sample of young people followed for 3 yr. The main findings were that high CRF at baseline was associated with higher academic achievement in Portuguese and foreign language (English) at follow-up, and that those who become fit achieved better school marks also in Portuguese and foreign language compared with those who were unfit at both time points.
These results further substantiate and extend the findings of previous cross-sectional studies (14,37) that observed that more fit students had better school performance. Several studies have demonstrated that CRF exhibits stronger associations with academic achievement than other physical fitness components (e.g., body composition, abdominal strength and endurance, upper body strength, and flexibility) (6,37,38).
Our results extend previous observations in that being categorized as consistently fit (fit/fit) as well as becoming fit (unfit/fit) during the 3-yr follow-up was associated with higher probability of attaining higher levels of academic achievement in Portuguese and foreign language at follow-up. Similarly, Chaddock et al. (5) analyzed whether childhood CRF predicted cognitive performance 1 yr later and observed that CRF was associated with cognitive control in cross-sectional and 1-yr prospective analyses. These findings may suggest that fit children have a better capability to allocate cognitive control processes and that this may persist over time and may determine future academic achievement (5).
When examining trajectories of CRF in relation to academic achievements, we observed that students who were persistently fit (fit–fit) had higher odds to achieve high levels of academic achievement in Portuguese and foreign language, compared with those who were consistently unfit (unfit–unfit). Although high CRF has been suggested to be associated with increased academic achievement (14,37), being consistently fit over time seems to be important to obtain better academic achievement as observed previously (6,39). Nonetheless, for those who were categorized as unfit at baseline and improved their fitness status during follow-up, a positive impact on their academic achievement was observed in Portuguese and foreign language when compared with consistently unfit individuals. This suggests that improvement in CRF might be associated with better academic achievement at least in language-related subjects.
Some potential mechanisms may explain the association between CRF and academic performance. Students with better academic achievement are more oriented for success; therefore, they may strive to achieve success in both academics and physical fitness (35). Another reason may be that physical fitness may enhance students’ concentration and improve classroom behavior (34), which is directly related to academic achievement. In addition, previous studies have demonstrated that CRF stimulates neural development, increasing the density of neuronal synapses (26), and increase the vasculature in the cerebral cortex (13), and it is associated with the recruitment of neural resources related to the effectiveness of adapting to task demands and fatigue (4). Moreover, CRF is also related to the microstructure of white fiber tracts in the brain during childhood, which is one pathway to improve cognitive and academic achievement (2,3). At a biochemical level, previous research has shown that PA and physical fitness enhance the synthesis of the brain-derived neurotrophic factor (BDNF) (10,30). An increase in BDNF is associated with increases in the volume of the hippocampus as well as improved memory (10,12). The activity of the BDNF is also related to increased long-term potentiation and neurogenesis (30).
Findings from the present study, along with others (6,27,39), suggest that investment in children and adolescent’s CRF levels may indirectly contribute to an investment in their academic performance. Therefore, achieving and maintaining a healthy level of CRF should be a priority for education in general and physical education in particular.
The present study has several strengths. The longitudinal design makes it possible to analyze the relationship between academic achievement and CRF at different time points and to follow the CRF trajectory over 3 yr. CRF was assessed with the PACER test, using clearly defined fitness standards aimed to differentiate students into different fitness levels. Although less accurate than the measured maximal oxygen uptake by indirect calorimetry, the PACER test is easily administered and provides a valid estimate of CRF (31). The academic achievement as assessed by four different disciplines reinforced the role of CRF in different academic areas.
Some limitations warrant mention when interpreting the findings from this study. We cannot exclude the possibility that our results are explained by unmeasured confounders. For example, CRF did not predict academic achievement when PA, obesity, and mothers’ education were controlled for (25). Unfortunately, individual data of socioeconomic status, home background, and parents’ education were not available. Although high fitness levels appear positively associated with academic achievement, socioeconomic status may be the strongest correlate of academic achievement (7). Thus, future prospective studies in which additional potential confounding factors are taken into account are needed to confirm or refute our observations. Furthermore, the use of categorical marks in four subjects as a proxy for achievement rather than standardized cognitive tests may be a limitation due the fact that students’ marks may be related to other factors beside their cognitive performance.
Our results suggest that those who are consistently fit or increase their CRF over a 3-yr period have an increased odd of higher academic performance in Portuguese and foreign language compared with those categorized as unfit. These findings support the need to modify public health and educational policy to encourage schools and physical education teachers to work in order to improve children and adolescents’ physical fitness. Outside school, the promotion of PA is also important because it does not appear to be detrimental to children and adolescents’ academic performance (9) and it contributes to the improvement of physical fitness.
CRF is associated with academic success in Portuguese and foreign language. Attention to these findings should be paid because of the implications it may have on student’s education, predominantly in societies where economic development is so important. With an increasing emphasis on the so-called academic disciplines, such as languages, mathematics, and sciences, decision-makers are under pressure to adhere to high academic standards. This may have implications on the curricula limiting time for PA and physical education, which in turn may negatively have impact on students’ physical fitness. Considering the relationship between CRF and academic achievement, low levels of CRF can jeopardized students’ academic future. Therefore, an investment in physical education is important because it might play a role in the positive effect of PA, fitness, and consequently cognition and academic success (1).
In conclusion, the main findings of the present study were that consistently high and improvements in CRF are prospectively associated with better academic achievement. High CRF at baseline was associated with higher academic achievement at follow-up, and that those who became fit achieved better school marks compared with those who were unfit at both time points.
We thank the children for their participation in the study and the physical education teachers for their assistance in helping with the collection of data.
The authors declare that there are no conflicts of interest. This study was not funded.
The results of the present study do not constitute endorsement by the American College of Sports Medicine.
1. Ardoy DN, Fernandez-Rodriguez JM, Jimenez-Pavon D, Castillo R, Ruiz JR, Ortega FB. A physical education trial improves adolescents’ cognitive performance and academic achievement: the EDUFIT study. Scand J Med Sci Sports
. 2014; 24(1): e52–61.
2. Chaddock-Heyman L, Erickson KI, Holtrop JL, et al. Aerobic fitness is associated with greater white matter integrity in children
. Front Hum Neurosci
. 2014; 8: 584.
3. Chaddock-Heyman L, Erickson KI, Kienzler C, et al. The role of aerobic fitness in cortical thickness and mathematics achievement in preadolescent children
. PLoS One
. 2015; 10(8): e0134115.
4. Chaddock L, Erickson KI, Prakash RS, et al. A functional MRI investigation of the association between childhood aerobic fitness and neurocognitive control. Biol Psychol
. 2012; 89(1): 260–8.
5. Chaddock L, Hillman CH, Pontifex MB, Johnson CR, Raine LB, Kramer AF. Childhood aerobic fitness predicts cognitive performance one year later. J Sports Sci
. 2012; 30(5): 421–30.
6. Chen LJ, Fox KR, Ku PW, Taun CY. Fitness change and subsequent academic performance in adolescents. J Sch Health
. 2013; 83(9): 631–8.
7. Coe DP, Peterson T, Blair C, Schutten MC, Peddie H. Physical fitness, academic achievement, and socioeconomic status in school
-aged youth. J Sch Health
. 2013; 83(7): 500–7.
8. Cooper Institute. Fitnessgram/Activitygram: Test Administration Manual
. Champaign: Human Kinetics; 2007.
9. Corder K, Atkin AJ, Bamber DJ, et al. Revising on the run or studying on the sofa: prospective associations between physical activity
, sedentary behaviour, and exam results in British adolescents. Int J Behav Nutr Phys Act
. 2015; 12(1): 106.
10. Cotman CW, Berchtold NC, Christie LA. Exercise
builds brain health: key roles of growth factor cascades and inflammation. Trends Neurosci
. 2007; 30(9): 464–72.
11. Donnelly JE, Greene JL, Gibson CA, et al. Physical Activity
Across the Curriculum (PAAC): a randomized controlled trial to promote physical activity
and diminish overweight and obesity in elementary school children
. Prev Med
. 2009; 49(4): 336–41.
12. Erickson KI, Voss MW, Prakash RS, et al. Exercise
training increases size of hippocampus and improves memory. Proc Natl Acad Sci U S A
. 2011; 108(7): 3017–22.
13. Etnier JL, Salazar W, Landers DM, Petruzzello SJ, Han M, Nowell P. The influence of physical fitness and exercise
upon cognitive functioning: a meta-analysis. J Sport Exerc Psychol
. 1997; 19(3): 249–77.
14. Haapala EA. Cardiorespiratory fitness and motor skills in relation to cognition and academic performance in children
—a review. J Hum Kinet
. 2013; 36: 55–68.
15. Haapala EA, Poikkeus AM, Tompuri T, et al. Associations of motor and cardiovascular performance with academic skills in children
. Med Sci Sports Exerc
. 2014; 46(5): 1016–24.
16. Hansen DM, Herrmann SD, Lambourne K, Lee J, Donnelly JE. Linear/nonlinear relations of activity and fitness with children
’s academic achievement. Med Sci Sports Exerc
. 2014; 46(12): 2279–85.
17. Harriss DJ, Atkinson G. Update—ethical standards in sport and exercise
science research. Int J Sports Med
. 2011; 32(11): 819–21.
18. Hillman CH, Buck SM, Themanson JR, Pontifex MB, Castelli DM. Aerobic fitness and cognitive development: event-related brain potential and task performance indices of executive control in preadolescent children
. Dev Psychol
. 2009; 45(1): 114–29.
19. Hillman CH, Castelli DM, Buck SM. Aerobic fitness and neurocognitive function in healthy preadolescent children
. Med Sci Sports Exerc
. 2005; 37(11): 1967–74.
20. Hillman CH, Erickson KI, Kramer AF. Be smart, exercise
your heart: exercise
effects on brain and cognition. Nat Rev Neurosci
. 2008; 9(1): 58–65.
21. Hillman CH, Pontifex MB, Castelli DM, et al. Effects of the FITKids randomized controlled trial on executive control and brain function. Pediatrics
. 2014; 134(4): e1063–71.
22. Hillman CH, Pontifex MB, Motl RW, et al. From ERPs to academics. Dev Cogn Neurosci
. 2012; 2(1 Suppl): S90–8.
23. Huang T, Tarp J, Domazet SL, et al. Associations of adiposity and aerobic fitness with executive function and math performance in Danish adolescents. J Pediatr
. 2015; 167(4): 810–5.
24. Janak JC, Gabriel KP, Oluyomi AO, Peréz A, Kohl HW, Kelder SH. The association between physical fitness and academic achievement in Texas State House Legislative Districts: an ecologic study. J Sch Health
. 2014; 84(8): 533–42.
25. Kantomaa MT, Stamatakis E, Kankaanpaa A, et al. Physical activity
and obesity mediate the association between childhood motor function and adolescents’ academic achievement. Proc Natl Acad Sci U S A
. 2013; 110(5): 1917–22.
26. Kramer AF, Colcombe S, Erickson K, et al. Effects of aerobic fitness training on human cortical function: a proposal. J Mol Neurosci
. 2002; 19(1–2): 227–31.
27. London RA, Castrechini S. A longitudinal examination of the link between youth physical fitness and academic achievement. J Sch Health
. 2011; 81(7): 400–8.
28. Moore RD, Drollette ES, Scudder MR, Bharij A, Hillman CH. The influence of cardiorespiratory fitness on strategic, behavioral, and electrophysiological indices of arithmetic cognition in preadolescent children
. Front Hum Neurosci
. 2014; 8: 258.
29. Moore RD, Wu CT, Pontifex MB, et al. Aerobic fitness and intra-individual variability of neurocognition in preadolescent children
. Brain Cogn
. 2013; 82(1): 43–57.
30. Ratey JJ, Loehr JE. The positive impact of physical activity
on cognition during adulthood: a review of underlying mechanisms, evidence and recommendations. Rev Neurosci
. 2011; 22(2): 171–85.
31. Saint-Maurice PF, Welk GJ, Finn KJ, Kaj M. Cross-validation of a PACER prediction equation for assessing aerobic capacity in Hungarian youth. Res Q Exerc Sport
. 2015; 86(1 Suppl): S66–73.
32. Sardinha LB, Marques A, Martins S, Palmeira A, Minderico C. Fitness, fatness, and academic performance in seventh-grade elementary school
students. BMC Pediatr
. 2014; 14(1): 176.
33. Scudder MR, Federmeier KD, Raine LB, Direito A, Boyd JK, Hillman CH. The association between aerobic fitness and language processing in children
: implications for academic achievement. Brain Cogn
. 2014; 87: 140–52.
34. Singh A, Uijtdewilligen L, Twisk JW, van Mechelen W, Chinapaw MJ. Physical activity
and performance at school
: a systematic review of the literature including a methodological quality assessment. Arch Pediatr Adolesc Med
. 2012; 166(1): 49–55.
35. Thogersen-Ntoumani C, Ntoumanis N. The role of self-determined motivation in the understanding of exercise
-related behaviours, cognitions and physical self-evaluations. J Sports Sci
. 2006; 24(4): 393–404.
36. Torrijos-Nino C, Martinez-Vizcaino V, Pardo-Guijarro MJ, Garcia-Prieto JC, Arias-Palencia NM, Sanchez-Lopez M. Physical fitness, obesity, and academic achievement in schoolchildren. J Pediatr
. 2014; 165(1): 104–9.
37. Van Dusen DP, Kelder SH, Kohl HW 3rd, Ranjit N, Perry CL. Associations of physical fitness and academic performance among schoolchildren. J Sch Health
. 2011; 81(12): 733–40.
38. Welk GJ, Jackson AW, Morrow JR Jr, Haskell WH, Meredith MD, Cooper KH. The association of health-related fitness with indicators of academic performance in Texas schools. Res Q Exerc Sport
. 2010; 81(3 Suppl): S16–23.
39. Wittberg RA, Northrup KL, Cottrell LA. Children
’s aerobic fitness and academic achievement: a longitudinal examination of students during their fifth and seventh grade years. Am J Public Health
. 2012; 102(12): 2303–7.