METABOLIC AND CARDIOVASCULAR MARKER ALTERATIONS DURING CRITICAL TRAINING IN WILDLAND FIREFIGHTERS

Abstract

Introduction: Wildland firefighters (WLFFs) are confronted with numerous physical and mental stressors. Pre-fire season includes an intense 2-week critical training (CT) period; a preparatory phase of multiple activities that can result in injury, illness, and rhabdomyolysis. The purpose of this study was to identify physiologic changes in metabolic, inflammatory, and oxidative stress biomarkers during 2 weeks of CT in WLFFs. Methods: Eighteen male (29.4 ± 1.1 yr, 182.1 ± 1.6 cm) and three female (26.7 2.6 yr, 169.5 4.2 cm) participants were recruited from a Type I interagency hotshot crew and monitored over their 2-week CT. Fitness was assessed via BLM Fitness Challenge (push-ups, pull-ups, sit-ups, 1.5-mile run). Subjects were asked to fast and abstain from caffeine prior to blood draws collected on days 1, 4, 8, and 11. Plasma was analyzed for changes in the metabolic profile, C-reactive protein (CRP) and oxidative stress markers 8-isoprostane (8ISO), 3-nitrotyrosine (3NT), lipid hydroperoxides (LOOH), and protein carbonyls (PC). A one-way repeated measures ANOVA was used to analyze CRP, 8ISO, 3NT, LOOH, and PC. Paired samples t-tests were used to compare metabolic biomarkers. Data presented as mean ± SEM. Results: As a result of the high physical demands occurring during CT, an observed alteration in total cholesterol (172.6 ± 11.4 to 153.9 ± 8.1 mg·dL-1, p=0.011), hemoglobin A1c (5.2 ± 0.1 to 5.1 ± 0.1 %, p=0.003), and estimated plasma volume (53.8 ± 0.7 to 59.3 ± 1.5 %, p=0.007) from day 1 to 11 occurred. No alteration to CRP (p=0.32) or PC (p=0.73) was observed during this time. A main effect for time was observed in 8ISO (p\u3c0.001), 3NT (p=0.033), and LOOH (p=0.001). Push-up score was significantly correlated with TC (r=0.65, p=0.022) and 8ISO (r=0.66, p=0.028). Conclusions: These data suggest the exertion required of WLFFs during CT results in positive alterations to the metabolic profile. The changes in oxidative damage markers is suggestive of an acute stress on the body during CT. The fitness data suggests that WLFF adapt quickly to the physical stresses of CT, with fitness potentially offering protection to metabolic alterations