Simulation of thermal-work strain of dismounted Marines wearing different body armor protection levels in a jungle environment

Authors

  • Alexander P Welles U.S. Army Research Institute of Environmental Medicine (USARIEM)
  • Mark J Buller U.S. Army Research Institute of Environmental Medicine (USARIEM)
  • Adam W Potter U.S. Army Research Institute of Environmental Medicine (USARIEM)
  • James A Balcius Marine Expeditionary Rifle Squad, Marine Corps Systems Command, 2200 Lester Street, Quantico, VA 22134-6050
  • Mark Richter Marine Expeditionary Rifle Squad, Marine Corps Systems Command, 2200 Lester Street, Quantico, VA 22134-6050

DOI:

https://doi.org/10.12922/jshp.v6i1.134

Keywords:

thermal-work strain, metabolic rate, modeling, thermal performance

Abstract

Dismounted warfighters often experience thermal-work strain when performing missions in hot and humid jungle environments. Under these conditions, the survivability benefits provided by increased body armor protection levels (BAPL) must be carefully balanced with their associated thermal and metabolic burdens and avoid thermal injury. PURPOSE: Model the effects of increased BAPL on the thermal-work strain of U.S. Marines engaged in dismounted training activities at Camp Gonsalves, Okinawa, Japan (June, 2013). METHODS: Core temperature (TC), heart rate (HR), and accelerometry data were collected over 3 days (5-9 hr/day) from U.S. Marines (N = 11, age = 21 ± 2 yr, ht = 172 ± 4 cm, wt = 78.2 ± 1.9 kg, x̅ ± SD) using chest-worn physiological monitors and ingested thermometer pills. Metabolic rates, estimated from accelerometry data by matching modeled to observed TC values using a thermoregulatory model, used to predict the physiological effects of increased BAPL under jungle conditions (air temperature = 28.3 ± 0.8 ºC, relative humidity = 91 ± 7 %). RESULTS: Root mean square error between observed and modeled TC was 0.24 ± 0.09 ºC for BAPL 0, indicating reasonable metabolic rate estimations. Mean daily increases in TC were 0.3 ± 0.4 ºC, 0.7 ± 0.4 ºC, 2.8 ± 0.9 ºC, and 3.2 ± 0.9 ºC for observed data and data modeled with BAPL 0, 3, and 5 respectively. Modeling BAPL 0 with either increased load or reduced vapor permeability resulted in TC increases of 2.9 ± 0.8 ºC and 1.4 ± 0.6 ºC respectively. Differences between BAPL resulted in Modeled TC values > 39.5 ºC at 238 ± 65 minutes and 188 ± 42 hrs for BAPL 3 and 5. CONCLUSION: Predictive modeling indicates that the risk of thermal-work strain is severe given jungle conditions and increased BAPL. The mass of BAPL ensembles contributes more to thermal-work strain than reductions in ensemble permeability and evaporative heat loss.

Author Biography

  • Adam W Potter, U.S. Army Research Institute of Environmental Medicine (USARIEM)
    Adam Potter is a Research Physiologist and the Deputy Chief of the Biophysics and Biomedical Modeling Division (BBMD) at the U.S. Army Research Institute of Environmental Medicine (USARIEM). Prior to his work in research, he served on active duty in the U.S. Marine Corps, participating in real-world operations in Kosovo, Iraq, and Liberia. His military awards include: the Navy and Marine Corps Achievement Medal, Combat Action Ribbon, Marine Corps Good Conduct Medal, National Defense Service Medal, the Iraq Campaign Medal (w/Bronze Star), the Global War on Terrorism Service Medal, the Humanitarian Service Medal, and the Sea Service Deployment Ribbon (w/Bronze Star). Mr. Potter holds a Bachelor of Arts (BA) in Psychology from Cambridge College, a Masters of Business Administration (MBA) and a Master of Science (MS) in Sports and Health Sciences from American Military University, and is currently working towards a PhD in Biomedical and Health Informatics with a concentration in Nanomedicine from Rutgers University. As a Principle Investigator at USARIEM he leads non-human and human research protocols in the areas of thermal manikins, thermoregulatory modeling, metabolic cost studies, and real-time monitoring of physiological responses to various military operational activities. His research portfolio spans across the applied sciences, e.g., manikin testing, to the cutting-edge of product development, e.g., computer-based decision aids and wearable sensors.

References

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Published

2018-03-15

Issue

Vol. 6 No. 1 (2018): Journal of Sport and Human Performance

Section

Original Research Articles

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