Heat Strain Decision Aid (HSDA) accurately predicts individual-based core body temperature rise while wearing chemical protective clothing.

ABSTRACT

PURPOSE: We examined the accuracy of the Heat Strain Decision Aid (HSDA) as a predictor of core body temperature in healthy individuals wearing chemical protective clothing during laboratory and field exercises in hot and humid conditions. METHODS: The laboratory experiment examined three chemical protective clothing ensembles in eight male volunteers (age 24 ±â€¯6 years; height 178 ±â€¯5 cm; body mass 76.6 ±â€¯8.4 kg) during intermittent treadmill marching in an environmental chamber (air temperature 29.3 ±â€¯0.1 °C; relative humidity 56 ±â€¯1%; wind speed 0.4 ±â€¯0.1 m s-1). The field experiment examined four different chemical protective clothing ensembles in twenty activity military volunteers (26 ±â€¯5 years; 175 ±â€¯8 cm; 80.2 ±â€¯12.1 kg) during a prolonged road march (26.0 ±â€¯0.5 °C; 55 ±â€¯3%; 4.3 ±â€¯0.7 m s-1). Predictive accuracy and precision were evaluated by the bias, mean absolute error (MAE), and root mean square error (RMSE). Additionally, accuracy was evaluated using a prediction bias of ±0.27 °C as an acceptable limit and by comparing predictions to observations within the standard deviation (SD) of the observed data. RESULTS: Core body temperature predictions were accurate for each chemical protective clothing ensemble in laboratory (Bias -0.10 ±â€¯0.36 °C; MAE 0.28 ±â€¯0.24 °C; RMSE 0.37 ±â€¯0.24 °C) and field experiments (Bias 0.23 ±â€¯0.32 °C; MAE 0.30 ±â€¯0.25 °C; RMSE 0.40 ±â€¯0.25 °C). From all modeled data, 72% of all predictions were within one standard deviation of the observed data including 92% of predictions for the laboratory experiment (SD ±â€¯0.64 °C) and 67% for the field experiment (SD ±â€¯0.38 °C). Individual-based predictions showed modest errors outside the SD range with 98% of predictions falling <1 °C; while, 81% of all errors were within 0.5 °C of observed data. CONCLUSION: The HSDA acceptably predicts core body temperature when wearing chemical protective clothing during laboratory and field exercises in hot and humid conditions.