Cognitive performance of military men and women during prolonged load carriage

Abstract

BackgroundThis study evaluated cognitive workload in soldiers undertaking a long duration march wearing different loads.MethodsMilitary participants (n=12 men and n=10 women) performed four 3-hour loaded marches (12.25 km at 4.9 km/hour) wearing either 21 kg, 26 kg, 33 kg or 43 kg. During the march, accuracy and response time were measured using the verbal working memory n-back test (0, 1, 2 and 3) and two bespoke Go/No Go tests (visual/auditory) to assess inhibition of a pre-potent response.ResultsThe physical demands of the march increased with load and march duration but remained at moderate intensity. N-back test accuracy ranged from 74% to 98% in men and 62% to 98% in women. Reduced accuracy was observed as load and time increased. Accuracy during the visual Go/No Go test also reduced with load, accuracy ranged from 69% to 89% in men and 65% to 90% in women. No differences due to load or time were observed during completion of the auditory Go/No Go task; accuracy ranged from 93% to 97% in men and 77% to 95% in women. A number of participants were unable to complete the march due to discomfort. Reports of discomfort were more frequent in women, which may have contributed to the greater reductions in accuracy observed.ConclusionThese data provide further evidence that cognitive performance of military personnel can be affected during long duration loaded marching. Women reported discomfort from equipment more frequently than men, which may make them more susceptible to declines in cognitive performance. These findings highlight important considerations for equipment procurement.

Cognitive Performance changes during a 20-day Winter Military Training Course and the Following 10-day Recovery Period

“…Changes in performance were as high as 20% in some measures. The results supported previous studies that have reported the effects of prolonged exercise [ 17 ] and multi-stress environments [ 23–25 ] on cognitive performance. Armstrong et al [ 17 ] found 20 to 25% decrease in visual Go/NoGO task among men and women during prolonged load carriage and Friedl et al [ 23 ] found a 20% decrease in reasoning during multistressor exposure in summer Ranger training.…”

“…The results supported previous studies that have reported the effects of prolonged exercise [ 17 ] and multi-stress environments [ 23–25 ] on cognitive performance. Armstrong et al [ 17 ] found 20 to 25% decrease in visual Go/NoGO task among men and women during prolonged load carriage and Friedl et al [ 23 ] found a 20% decrease in reasoning during multistressor exposure in summer Ranger training. These findings highlight the need to understand, prepare and support cognitive performance in military operations in addition to physical and environmental factors.…”

The development, and day-to-day variation, of a Military-Specific Auditory N-Back Task and Shoot-/Don’t -Shoot Task

“…During the seated condition, participants recorded their answers, while during walking trials, participants were required to relay their answers verbally which were recorded on their behalf. The SDST was designed to be a visual search and inhibition task similar to those tasks previously employed within the literature (Armstrong et al, 2022; Eddy et al, 2015; Kobus et al, 2010). The assessment involved responding appropriately to targets and non-targets.…”

“…Failure to maintain performance, in either domain, can result in reduced combat readiness and decreased operational performance (Crawford et al, 2017; Vrijkotte et al, 2016). Consequently, there is growing interest in the relationship between military-specific physical activity and cognitive performance within military operators (Armstrong et al, 2022; Bhattacharyya et al, 2017; Eddy et al, 2015; Giles et al, 2019; Kobus et al, 2010; Nibbeling et al, 2014; Son et al, 2019, 2022; Vine et al, 2021). Despite this interest, the methodologies and approaches used to investigate this relationship have differed considerably, particularly concerning the assessment of cognitive performance.…”

Closing the gender gap in military health and performance: a special issue ofBMJ Military Health

“…Responding to a gender data gap in defence that is also evident in wider society, as described in the editorial by Greeves et al ,2 this supplement has been curated to evaluate sex differences in musculoskeletal injuries in training3 and the trained strength,4 the biomechanics of load carriage,5 the cognitive responses to load carriage,6 and the prevalence of, and risk factors for, mental ill-health 7. We also discuss unique challenges for women, including the prevalence of injury and illness on return to work following childbirth,8 and both the prevalence of hormonal contraceptive use9 and influence of hormonal contraceptive use on bone metabolism 10.…”