Physiological Factors Which Influence Cognitive Performance in Military Personnel

Abstract

Objective: To identify and detail physiological factors that influence cognition in military personnel. Background: Maintenance of cognitive and task performance is important under several scenarios, none more so than in a military context. Personnel are prepared for and trained to tolerate many of the stressors they encounter; however, consideration of stressors typically extends only as far as the physical, psychological, and environmental requirements of a given task. While considering these factors certainly characterizes the broader picture, several physiological states and traits can influence cognition and thus, should also be considered. Method: A systematic review of the electronic databases Medline (PubMed), EMBASE (Scopus), PsycINFO, and Web of Science was conducted from inception up to January 2019. Eligibility criteria included current military personnel, an outcome of cognition, and the assessment of a physiological factor. Results: The search returned 60,564 records, of which 60 were included in the review. Eleven studies examined the impact of demographic factors on cognition, 16 examined fatigue, 10 investigated nutrition, and 24 the impact of biological factors on cognitive performance. Conclusion: Factors identified as having a positive impact on cognition include aerobic fitness, nutritional supplementation, and visual acuity. In contrast, factors identified as having a negative impact include fatigue arising from sustained operations, dehydration, undernutrition, and an exaggerated physiological stress response to a cognitive task or a stressor. A further subset of these factors was considered modifiable. Application: The modifiable factors identified provide avenues for training and preparation to enhance cognition in ways previously unconsidered.

Portable Biosensors for Psychophysiological Stress Monitoring of a Helicopter Crew

“…Furthermore, the HR and SatO2 increased after the crane rescue maneuver, showing the organic adaptive response to the cardiorespiratory demands of the maneuver. This response was contrary to the low-altitude flight and other military combat situations where SatO2 decreased in the interventions [3,5,[7][8][9][10][11]13,27]. The higher demands of the crane rescue maneuver could be responsible for the decreases in the horizontal jump, FEV1, PEF, and ST • , which are signals of fatigue [5].…”

“…The analysis of the HRV showed an increase in the sympathetic modulation of both groups, measured in the increase in the mean HR and Max HR, reaching peak HR values during the crane rescue maneuver, specifically in the moment where the rescuer was performing the rescue from the helicopter using the crane. The large demand of the intervention, the lack of control, and the uncertainty produce the increase in the stress response through the increase in sympathetic modulation, affecting performance, reducing cardiopulmonary capacity and strength, and momentarily stopping the urine and intestinal processes in order to prioritize organic resources to maintain survival [1,3,7,10,11,14,29]. Specifically in the low-altitude flight, we found an increased anxiety response, probably related with the danger of the maneuver, since it was conducted at a low altitude, and any minimal failure could finish in a mortal accident; nevertheless, during the flight, the sympathetic modulation decreased, showing the habituation expected from highly trained subjects [16].…”

“…Independently of the combat situation, in military deployments, there are unpredictable and unknown hazards that elicit a stress response in the organism [2]. This response activates the fight-flight system and the physiological mechanisms that are basic to survival, also affecting cognitive processes, such as information processing, memory, perception, attention, judgement, and decision-making, as well as physical aspects, such as endurance, strength, and flexibility [1,[3][4][5][6]. The continuous exposure to the combat stressors of military populations and air force crews have been previously related with mental disorders, such as post-traumatic stress disorder (PTSD) [7], highlighting the importance of personalized training based on a better understanding of the psychological and physiological responses involved in stress coping mechanisms.…”

Can Physiological and Psychological Factors Predict Dropout from Intense 10-Day Winter Military Survival Training?

“…Therefore, conscripts with lower aerobic fitness may have reached the level of physical and/or mental exhaustion well before those with higher fitness, and the exhaustion may have exposed them for drop out. This is important given that in addition to better stress tolerance, higher aerobic fitness has been associated with improved ability to maintain cognitive performance within the military context [37]. Strength and power do not have similar predictive power to higher risk for dropout, probably in part, because these fitness components do not similarly prevent accumulated fatigue during military field training than aerobic fitness.…”

Cognitive task performance under (combined) conditions of a metabolic and sensory stressor

“…In the end, this kind of research can be applied to get insight into mechanisms underlying the stressors, which can lead to better countermeasures that prevent or alleviate negative effects of combined stressors on performance (Martin et al 2020). Taking a comprehensive approach of performance, physiological and subjective measures to study the impact of stressors on cognition might be valuable in strengthening industrial safety.…”