Inflammatory and psychological consequences of chronic high exposure firefighting.

OBJECTIVES: This study aimed to examine the impact of extreme heat exposure frequency on inflammation and well-being in UK Fire Service personnel. METHODS: 136 Fire personnel and 14 controls (CON) were recruited [92 Firefighters (FF), 44 Breathing Apparatus Instructors (BAI)]. BAI were split into low (LBAI; ≤15 exposures per month) and high (HBAI; ≥20 exposures per month) categories. Measures of inflammation, mood and fatigue were collected at 0, 3 and 6 month times points. These variables were analysed for differences between groups and association with frequency of exposure. RESULTS: HBAI exhibited raised IL-1ß, IL-6, IL-10, IgE and lower IgM (p < 0.05). In addition, IL-1ß, IL-6, IL-10 and IgM were associated with monthly exposure number, with exposures accounting for 15.4% of the variance in IL-6, 11.8% of IL-1ß and 25.2% of IL-10. No differences in mood or fatigue were reported (p > 0.05). CONCLUSION: High exposure firefighting consistently causes systemic inflammation without perceptual recognition of potential health risks.

Optimizing the Use of Phase Change Material Vests Worn During Explosives Ordnance Disposal Operations in Hot Conditions.

Phase change material (PCM) cooling garments' efficacy is limited by the duration of cooling provided. The purpose of this study was to evaluate the effect of replacing a PCM vest during a rest period on physiological and perceptual responses during explosive ordnance disposal (EOD) related activity. Six non-heat acclimated males undertook three trials (consisting of 2 × 3 × 16.5 min activity cycles interspersed with one 10 min rest period) in 40°C, 12% relative humidity whilst wearing a ≈38 kg EOD suit. Participants did not wear a PCM cooling vest (NoPCM); wore one PCM vest throughout (PCM1) or changed the PCM vest in the 10 min rest period (PCM2). Rectal temperature (T re ), mean skin temperature (T skin ), heart rate (HR), Physiological Strain Index (PSI), ratings of perceived exertion, temperature sensation and thermal comfort were compared at the end of each activity cycle and at the end of the trial. Data displayed as mean [95% CI]. After the rest period, a rise in T re was attenuated in PCM2 compared to NoPCM and PCM1 (-0.57 [-0.95, -0.20]°C and -0.46 [-0.81, -0.11]°C, respectively). A rise in HR and T skin was also attenuated in PCM2 compared to NoPCM and PCM1 (-23 [-29, -16] beats⋅min-1 and -17 [-28, -6.0] beats⋅min-1; -0.61 [-1.21, -0.10]°C and -0.89 [-1.37, -0.42]°C, respectively). Resulting in PSI being lower in PCM2 compared to NoPCM and PCM1 (-2.2 [-3.1, -1.4] and -0.8 [-1.3,-0.4], respectively). More favorable perceptions were also observed in PCM2 vs. both NoPCM and PCM1 (p < 0.01). Thermal perceptual measures were similar between NoPCM and PCM1 and the rise in T re after the rest period tended to be greater in PCM1 than NoPCM. These findings suggest that replacing a PCM vest better attenuates rises in both physiological and perceptual strain compared to when a PCM vest is not replaced. Furthermore, not replacing a PCM vest that has exhausted its cooling capacity, can increase the level of heat strain experienced by the wearer.