Effect of a Simulated Tactical Occupation Stressor on Immune System Markers of Physiological Stress and Inflammation: 2953 Board #236 June 1 3 30 PM - 5 00 PM

PURPOSE: Walker et al., 2015 reported that increases in immune system markers [interleukin-6 (IL-6), C-reactive protein (CRP)] occur simultaneously with each increase in core temperature. A substantial physiological and psychological disturbance experienced by firefighters could potentially lead to a depression in immune system function. The purpose of this study was to evaluate specific immune system markers in response to a simulated firefighting occupation workload. METHODS: Ten healthy male adults participated in this study. While wearing proper testing attire, participants completed a simulated fire stair climb (SFSC) by completing two consecutive 3-min workloads on a Matrix C7xe ClimbMill (Matrix Fitness USA, Cottage Grove, WI, USA) at a stepping rate of 60 steps/min. The participants completed this protocol under four conditions, with some conditions including the wearing of a 34.04 kg (75 lbs) weighted vest to simulate the wearing of personal protective equipment (PPE) typically worn by a firefighter. Some conditions involved the inclusion of a color-word interference test (CWIT) as a distracting mechanism. Salivary cortisol (CORT) was measured at baseline, following initial 3 min workload, and following completion of total workload. CRP was evaluated at baseline and one hour following the completion of each workload. RESULTS: A repeated-measures ANOVA showed that there was a significantly different blood lactate when comparing conditions (p < 0.0005). Both Conditions 2 and 4 exhibited a significantly higher BL (p < 0.05) than Conditions 1 and 3. There were not shown to be any significant differences (p > 0.05) as a result of the SFSC between Conditions 2 and 4 or any differences between Conditions 1 and 3 in regards to BL. Neither CORT (p = 0.116) or CRP (p = 0.700) was shown to be significantly different across conditions or from baseline. CONCLUSIONS: Based on the results of the current study, it appears that the wearing of a weighted vest to simulate PPE significantly elevates BL above what would be expected by the exercise alone. This illustrates the significant increase in exercise intensity while wearing the simulated PPE. However, the degree of exercise employed was not enough (with or without the weighted vest) to elicit any substantial changes in inflammatory markers.