Soldiers Physical Strains and Cognitive Performance during a Marine Course

Abstract

Nowadays soldiers have to operate under extreme circumstances for long periods of time, for example in Iraq, Bosnia and Afghanistan. Soldiers easily cross their limits of physical and cognitive functioning because they are exposed to complex, extreme and sustained operations. These circumstances have a negative influence on soldier's performance and operational readiness/status. Commanders predict soldier's readiness based on their own observations and personal experiences. Inadequate estimation of operational readiness can lead to dangerous situations. Therefore, an objective method, giving insight in soldier's physical and cognitive status, needs to be developed to support commander's decision-making processes as well as to guard soldier's safety and health. PURPOSE: Getting insight in the physical and cognitive performance (and their inter-reliability) of soldiers during sustained operations. These insights can be used to develop a tool to predict operational readiness. METHODS: Physical and cognitive performance was measured using a field lab. During a 9-month Marine Course, 16 soldiers were measured during two periods; eight days during the course in the Netherlands and fourteen days during the course in the United Kingdom. Continuously physical monitoring took place, measuring heart rate, core- and skin temperature and respiration rate. Cognition and subjective ratings were measured three times a day in the Netherlands and twice a day in the UK, assessing logical reasoning, working memory, alertness (using the N-Back, Tower of Hanoi and VigTrack), exertion, sleep, and effort. RESULTS: Physiology measurements show that soldiers were exposed to higher physical strains in the Netherlands compared to the UK. Performance on the cognitive tasks decreased over time during both test periods. Performance decreased the most in the Netherlands (a 30% decrease compared to an almost 10% decrease in the UK). CONCLUSIONS: Soldiers were unable to maintain cognitive performance over time during the test periods. Cognitive performance decreased most in the Netherlands where soldiers experienced higher physical strains compared to the UK. Whether physical strain and cognitive performance are related remains to be investigated.