Respostas cognitivas após uma atividade de marcha em militares do curso de operações especiais

Abstract

INTRODUCTION: Cognitive performance has been shown to be important for the execution of a wide range of military tasks, for example, inhibitory control for the correct execution of a shot in an uncontrolled environment or receiving and executing orders under fire. The benefits of physical activity on cognition are widely reported, however, military tasks are frequently associated with extremely strenuous physical demands, in addition, these demands usually take place in challenging circumstances and harsh environments. These factors in conjunction can accumulate, inducing a state of physical and/or mental fatigue, which can have a direct impact on cognitive performance as well as on task completion. Therefore, the objective of the present study is to verify the acute effect of a load carriage march activity in military personnel, that are attending the Special Operations course, on cognitive capacity in a selective attention task. METHODS: 21 subjects (age: 29.8 [28.1 – 31.4], weight: 79.6kg [77.1 – 82.1], height: 177cm [1.75 – 1.79]), currently attending the Special Operations course, undertook a cognitive performance assessment test (Word and Color Stroop Test) before and after a long marching activity with load carriage (17h), with the equipment weighting approximately 35kg. A T test for paired samples was carried out to assess the difference between conditions. All procedures were approved by the local ethics committee. RESULTS: It was found a significant difference in the variable “accuracy” (96.7% vs 93.5%, p = 0.016). No other difference was reported in the variables “reaction time” (2.17s vs 2.21s, p = 0.688), “reaction time of correctly responded stimuli” (2.25s vs 2.39s, p = 0.894), “total responded stimuli” (146 vs 145, p = 0.467) “correctly responded stimuli” (141 vs 137, p = 0.255). CONCLUSION: The main finding of this study indicates that the stress caused by marching with load carriage led to an acute reduction in cognitive performance in experienced military personnel. However, it is not clear how much effect was caused exclusively by the physical fatigue generated by carrying out the activity and how much other factors, such as dehydration and hyperthermia, may have influenced the result.