Physiological and kinematic biomarkers for optimal performance and safety in the heat

Abstract

Introduction: During Arctic operations, the difficulties of safely mobilizing ground forces in extreme cold environments becomes particularly apparent given the high diversity between individuals in morphology, in physiological capabilities, psychological preparedness and in genetic makeup. Understanding potential risk factors for cold weather injuries in individual operators is key to reduce casualties, maintain performance and ensure mission success. The purpose of this research program is to better understand and identify the factors that predict individual physiological and psychological responses to the cold, which may be key to maintain the ability to sustain performance in such environments. Methods: Through an international collaborative effort, our research team has developed a systematic laboratory-based cold evaluation method which includes a detailed characterization of individuals (body shape and composition) and a highly standardized cold test to predict key physiological and psychological markers of cold operational readiness (i.e., shivering, dexterity, risks of developing cold weather injuries, cognitive capacity, mood, thermal comfort, and fatigue). Results: The pilot data confirmed the extremely large variability in cold responses in women and men during the cold test. We also found that body mass may be the greatest determinant for cold tolerance and affects not only the amount of shivering that occurs but also hand temperature and thermal comfort. Conclusions and future research: Systematically identifying key individual biomarkers of cold response is an essential first step in providing individualized cold weather training, proper clothing solutions and operational guidelines. In follow-up work, a cold-weather screening tool will be developed and used during cold weather training and operations to refine the model. Additional laboratory trials will be conducted to refine the cold weather screening tool algorithm in response to these pre-exposure interventions. Such a cold screening tool is essential for adapting training and to determine potential decreases in performance capabilities for Arctic operators.