Educação física escolar, aptidão física e seu papel sobre a função cognitiva

Abstract

Studies indicate a relationship between physical fitness and cognitive functions, among those functions; the executive functions have been more studied because of the biggest association with academic achievement. In this sense, it is possible to suppose that some biochemical parameters are related to this fact, on the other hand, no studies were done using these salivary markers and their associations with the physical fitness and the cognitive functions. The objective of this study was to measure the relationship between physical fitness and executive function together with biochemical markers in schoolchildren, as well as the acute effect of physical exercise in these parameters. Cognitive function was assessed by two tests: Stroop test (ST), to evaluate selective attention and inhibitory control and Tower of Hanoi (ToH) that assess work memory through transferring a pyramid rings from one pin to another. Cardiorespiratory fitness was evaluated by run/walk six-minute test and muscular endurance was assessed by one-minute sit-up test. Physical fitness was evaluated based on Brazilian reference values provided by PROESP-BR databank and biochemical analyzes in both experiments were performed using saliva as biological fluid. Two studies were made: 1) The first was composed by thirty three students of ninth grade submitted to a cognitive assessment by ST and ToH, together with run/walk six minute test and one-minute sit-up test. 2) The second group had twenty students of sixth grade that were subjected to the ST at rest and immediately after the run/walk six-minute test. The students of the first study showed lower values of physical fitness in most subjects for run/walk six-minute test (91%) and one-minute sit-up test (94%). Boys had significantly higher fitness than girls for run/walk for six-minute test (+27%) and one-minute sit-up test (+26%). No significant differences were found on cognitive performance between both sexes. We observed a negative association of ST with distance running (r= -0,56, p<0.05) and with one-minute sit-up test (r= -0,55, p<0.05) in girls. On the other hand, boys did not show any significant associations for these tests. However a negative association was observed for one-minute sit-up test with number of movements in ToH (r= -0,48, p<0.05) and for salivary TBARs with performance time in ToH (r= 0,35, p<0.05). In the second experiment we also observed low cardiovascular fitness in most subjects (96%). Run/walk six-minute test promoted increased values for total protein (+67%, p<0.05), uric acid (+102%, p<0.05), GSH (+34%, p<0.05) and TBARs (+97%, p<0.05) in saliva. Interestingly, time to perform ST was decreased post-exercise (-9%, p<0.05). We also observed that salivary TBARs at rest showed a positive correlation with time performance in the ST (r = 0.46; p<0.03). Our results suggest that physical fitness is differently associated with cognitive performance in girls and boys. Besides that, we found that only 6 minutes of physical exercise acutely improves inhibitory control and selective attention, which indicates an important role of adequate levels of physical activity for schoolchildren regarding cognitive abilities.