- Meeting abstract
- Open Access
Soldiers' perceived versus actual heat strain in a jungle environment
© Fogarty et al.; 2015
- Published: 14 September 2015
- Body Core Temperature
- Laboratory Simulation
- Evaporative Heat Loss
- Heat Illness
- Body Armour
Soldiers are regularly required to work in hot environments whilst wearing protective body armour (BA). However, BA is impermeable and decreases the torso surface area available for evaporative heat losses . Consequently, an elevation in body core temperature was observed with early versions of BA [2, 3]. In recent years, the size (and surface area coverage) of BA has decreased and laboratory simulations have shown that this newer BA does not increase the physiological load to the same extent as previous systems . Anecdotally, however, Australian soldiers continue to report feeling an increased thermal burden when wearing BA. Therefore, we investigated the disconnect between experience and laboratory trials of the thermal impact of wearing BA in a warm jungle environment.
Thirty-one Australian soldiers undertook two activities (three days of patrolling and a section competition including a march, a battle run, an obstacle course and a bayonet assault course) wearing either BA and webbing (BAW) or webbing (W) only while undertaking jungle training. Although the groups were not matched due to operational constraints, there were no significant differences between the groups in anthropometric measures or aerobic capacity. Heart rate (HR) and body core temperature (Tc) were measured using a physiological monitoring system. Perceived heat illness symptoms were measured using the Environmental Symptoms Questionnaire (ESQ; 22 statements) . Environmental conditions were measured using a wet bulb globe thermometer (WBGT).
The WBGT was 24-25 °C and 20 °C for the section patrol days and section competition respectively. The physiological measures (HR and Tc) were not significantly different between the BAW and W groups during both activities. The summed ESQ rating was not different between groups during the patrol days, however six individual statements were higher with the BAW group. In contrast, after the section competition both the sum of ratings and 7 statements were significantly higher in the BAW group.
Similar to laboratory simulations, BA (with reduced surface area) did not impose a greater thermal strain on soldiers in a warm jungle environment. Despite this finding, the ESQ indicates that the soldiers wearing BA perceived that they were under greater thermal strain.
The findings of the present study suggest that, if operational needs require soldiers to wear BA in a jungle environment, there is not an increased risk of personnel becoming a heat casualty. However, soldiers perceive themselves to be more uncomfortable and thus may be less able to concentrate on the mission.
- Pascoe DD, Shanley LA, Smith EW: Clothing and exercise. I: Biophysics of heat transfer between the individual, clothing and environment. Sports Med. 1994, 18 (1): 38-54. 10.2165/00007256-199418010-00005.View ArticlePubMedGoogle Scholar
- Goldman RF: Physiological costs of body armour. Military Medicine. 1969, 134 (3): 204-10.PubMedGoogle Scholar
- Haisman MF, Goldman RF: Physiological Evaluations of Armoured Vests in Hot-Wet and Hot-Dry Climates. Ergonomics. 1974, 17 (1): 1-12. 10.1080/00140137408931307.View ArticlePubMedGoogle Scholar
- van den Heuvel AMJ, et al: The effect of a four-tier body armour system on body-heat retention and physiological strain. UOW-CHAP-HPL-Report-040. 2010, Wollongong, University of WollongongGoogle Scholar
- Sampson JB, Kobrick JL, Johnson RF: Measurement of subjective reactions to extreme environments: The environmental symptoms questionnaire. Military Psychology. 1994, 6 (4): 215-233.View ArticleGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.