Mitigation of heat strain through the USMC training continuum

Project Summary Abstract Heat related injury (HRI) increased 48% from 2008 to 2010 within the U.S. military and is continually identified as a major threat to the health and performance of the modern warfighter. Moreover, the incidence of heat stroke ranks highest within the Marine Corps compared to other branches of the service (Medical Surveillance Monthly Report, Vol 20, No 3, March 2013). The current USMC heat injury prevention strategies (Base Order 6200) provide direction on the pathology of heat injuries, weather condition issues and suggestions for hydrations strategies. Individual risk factors for HRI are briefly discussed (fitness, fatness) and it is mentioned that, 'These individuals should be identified and continually monitored by their supervisors and medical department personnel.' Our recent research efforts have demonstrated similar results with the modeling approaches we have used. These data demonstrate that aerobic fitness provides extensive protection against abnormal responses in the heat (exaggerated heart rate and core temperature drift), suggesting increased risk for exertional heat injury. Moreover, previously noted gold standard measures (core temperature) inadequately display the necessary response times and resolution to provide for accurate real-time measurements. Our data support the use of skin temperature and heart rate as key physiological metrics to identify heat related stress responses during real-time training and operations. Moreover, these metrics are less cumbersome to monitor (given the right technology) and more accurately reflect interactions with the ambient environment, equipment/clothing requirements and metabolic activity. The purpose of this project will be to leverage our previous data collection efforts that have identified known predictors for heat stress risk and align them with retrospective data on heat related injuries from clinics in North and South Carolina (Camp Lejeune and Parris Island). Additionally, our developed models will be used during field demonstrations on location. These field demonstrations will introduce personnel to our projected two-step approach to HRI heat stress mitigation (initial aerobic fitness parameter coupled with selective real-time physiological monitoring to ensure safety in training). It is anticipated that these demonstrations will be conducted at multiple locations where HRI risk is most prevalent within the USMC