Background Fire protective ensembles (FPEs) are essential to safely perform firefighting job tasks; however, they are often burdensome to the workers. The aim of this study was to compare three internationally certified fire protective ensembles from the European Union (EU), South Korea (SK), and United States (US) on physiological responses, mobility, and comfort. Methods Ten male professional firefighters performed a battery of exercises in the laboratory following the ASTM F3031-17 standard to evaluate mobility, occupation-specific performance, and physiological responses (body weight, heart rate (HR), core temperature (Tc), breathing rate (BR), and rating of perceived exertion (RPE)) to 20 min of treadmill walking (3.2 mph, 5% incline). All participants carried out the evaluation wearing each FPE in a random order. Mixed effects models examined time (pre-vs. post-) by ensemble (EU, SK, US) interactions for all physiological variables and compared comfort, performance, and subjective variables across ensembles. Results No interaction effects were observed for body weight, HR, Tc, BR, or RPE (p = 0.890, p = 0.994, p = 0.897, p = 0.435, and p = 0.221; respectively). SK had greater trunk flexion than EU (78.4° vs. 74.6°, p = 0.026) and US had lower standing reach than EU (105.5 cm vs. 115.4 cm, p = 0.004). Agility circuit time was lower in US (9.3 s) compared to EU (9.8 s) or SK (9.9 s) (p = 0.051 and p = 0.019, respectively). Conclusions The findings suggest that physiological burden remained largely unchanged across the international FPEs. However, mobility, performance, and comfort may be significantly influenced across types. International stakeholders and end users should consider design implications when choosing fire protective ensembles.

Introduction: Elevated ambient temperature and personal protective clothing (PPC) induce physiological strain which may be counteracted by heat acclimation. The purpose of this study was to determine if 5-day heat acclimation training (HAT) improves thermal and perceptual responses while wearing chemical, biological, radiological, and nuclear (CBRN) PPC. Methods: Nine healthy men completed a heat stress test (walking for one hour with CBRN PPC) in 35 degrees C and 50% relative humidity (RH) before and after 5-day HAT. The HAT consisted of five consecutive days of two 45-minute cycling sessions (50% VO2max) wearing athletic clothing separated by a 15 min rest in 45 degrees C and 20% RH. Results of the pre- and post- HAT heat stress tests were compared. Results: Heat acclimation was seen through 5-day HAT; however, thermoregulatory responses did not improve while wearing CBRN PPC. Improvement (p<0.05, day 1 vs. day 5 HAT) in skin temperature (38.0+/-0.5 degrees C vs. 37.6+/-0.5 degrees C), body temperature (38.6+/-0.4 degrees C vs. 38.3+/-0.4 degrees C), sweat rate (2.26+/-0.3kg vs. 2.64+/-0.3kg), RPE (15.8+/-2.4 vs. 13.9+/-3.1), and heat perception (5.7+/-0.6 vs. 4.9+/-1.0) were noted. However, no physiological or perceptual improvements (p>0.05) were found in the post-HAT heat stress test. Conclusions: Heat acclimation adaptations may be blunted by CBRN PPC, thus requiring differing or extended HAT.

BACKGROUND: Hypoxia and exercise each exhibit opposing effects on executive function, and the mechanisms for this are not entirely clear. This study examined the influence of cerebral oxygenation and perfusion on executive function during exercise and recovery in normobaric hypoxia (NH) and normoxia (N). METHODS: There were 18 subjects who completed cycling trials in NH (12.5% FIo2) and N (20.93% FIo2). Right prefrontal cortex (PFC) oxyhemoglobin (O2Hb) and middle cerebral artery blood velocity (MCAbv) were collected during executive function challenges [mathematical processing and running memory continuous performance task (RMCPT)] at baseline, following 30 min of acclimation, during 20 min of cycling (60% Vo2max), and at 1, 15, 30, and 45 min following exercise. RESULTS: Results indicated effects of time for Math, RMCPT, and O2Hb; but not for MCAbv. Results also indicated effects of condition for O2Hb. Math scores were improved by 8.0% during exercise and remained elevated at 30 min of recovery (12.5%), RMCPT scores significantly improved at all time points (7.5-11.9%), and O2Hb increased by 662.2% and 440.9% during exercise in N and NH, respectively, and remained elevated through 15 min of recovery in both conditions. DISCUSSION: These results support the influence of PFC oxygenation and perfusion on executive function during exercise and recovery in N and NH.Stavres J, Gerhart HD, Kim J-H, Glickman EL, Seo Y. Cerebral hemodynamics and executive function during exercise and recovery in normobaric hypoxia. Aerosp Med Hum Perform 2017; 88(10):911-917.

The purpose of the study was to compare body temperature responses from subjects who exercised while wearing firefighter clothing to predictive data from a real-time thermoregulatory model that had been initially developed and validated for use in the military. Data from two firefighter studies, firefighter study 1 (FFS1: 7 males and 3 females, continuous treadmill exercise at 50% VO2max, 25 °C, 50% RH) and firefighter study 2 (FFS2: 6 males, intermittent treadmill exercise at 75% VO2max, 35 °C, 50% RH), were utilized for the thermoregulatory modeling and comparison. The results showed that prediction error (RMSD) of the model for core and skin temperatures was 0.33 and 0.65 °C in FFS1 and 0.39 and 0.86 °C in FFS2, respectively. While the real-time thermoregulatory model tested in the present study showed the potential for providing a means for reasonably accurate prediction of body temperature responses in firefighters, further development on the model's metabolism algorithms to include adjustments for protective clothing, options to facilitate external work, inclusions of cooling effects are suggested. Relevance to industry Firefighters exposed to thermal extremes experience physiological strain, but direct monitoring of physiological variables is not always practical. Thermoregulatory models can simulate the thermal responses reasonably accurately by applying known thermo-physiological mechanisms together with heat loss mechanisms related to clothing and environment in an effort to improve firefighter safety.