Author(s): GLÄTTLI, A., GERBER, M., ANNEN, H., LUDYGA, S. , Institution: UNIVERSITY OF BASEL / MILITARY ACADEMY (MILAC) AT ETH ZURICH, Country: SWITZERLAND, Abstract-ID: 2261

Introduction
Working memory contributes to successful decision-making and goal-oriented thinking, a factor that is essential for flawless human performance as required in an operational setting. Military service is often characterized by sleep deprivation and physiological and psychological stress, which could further impede the optimal functioning of cognitive performance. It is therefore essential to identify factors that contribute to promoting working memory performance. Previous studies have found that high physical fitness is associated with better working memory performance (Oberlin et al., 2016). However, few studies have examined this link in young, healthy adults, particularly in a military setting. We therefore aimed to investigate the association of physical fitness with both behavioral and neurocognitive indices of working memory in recruits of the Swiss Armed Forces.
Methods
Our sample comprised 134 male recruits of an Infantry school with a mean age of 19.8 years. Physical fitness was assessed using the Swiss Army's official fitness test and conducted during basic military training, including a shuttle run and two strength tests (Wyss et al., 2019). Additionally, participants completed a computerized spatial N-back task. Electroencephalography was used to record event-related potentials (i.e., N2 and P3) evoked by this task.
Results
Aerobic endurance correlated positively with working memory accuracy (r = 0.27, p = 0.003). In contrast, performance on the two strength tests was not directly linked to working memory performance (r = -0.03, p = 0.73; r = -0.004, p = 0.97). Regarding neurocognitive indices, P3 latency was negatively correlated to the trunk muscle strength test (r = 0.21, p = 0.02). However, path analyses revealed no significant mediation of the association between working memory accuracy and performance on the shuttle run by P3 or N2.
Discussion
Recruits with higher aerobic endurance are also characterized by better working memory abilities, which are likely to contribute to informed decision making. These findings could have practical implications for military education and training. However, the underlying physiological mechanism of this association needs further investigation.
References
Oberlin, L. E., Verstynen, T. D., Burzynska, A. Z., Voss, M. W., Prakash, R. S., Chaddock-Heyman, L., Wong, C., Fanning, J., Awick, E., Gothe, N., Phillips, S. M., Mailey, E., Ehlers, D., Olson, E., Wojcicki, T., McAuley, E., Kramer, A. F., & Erickson, K. I. (2016). White matter microstructure mediates the relationship between cardiorespiratory fitness and spatial working memory in older adults. NeuroImage, 131, 91–101.
Wyss, T., Roos, L., Studer, F., Mäder, U., Beuchat, C., & Staub, K. (2019). Development of physical fitness performance in young Swiss men from 2006 to 2015. Scandinavian Journal of Medicine & Science in Sports, 29(4), 586–596.