Objective:To identify physiologic stressors related to cardiovascular disease via changes in metabolic, inflammatory, and oxidative stress biomarkers during 2 weeks of preseason training in wildland firefighters (WLFFs).

Methods:Participants were recruited from a local hotshot crew and monitored during preseason training. Fitness was assessed via the Bureau of Land Management fitness challenge. Venipuncture blood was collected on days 1, 4, 8, and 11 and analyzed for changes in a lipid and glucose panel, C-reactive protein, and oxidative stress markers 8-isoprostane (8ISO), 3-nitrotyrosine (3NT), lipid hydroperoxides (LOOH), and protein carbonyls.

Results: The high physical demands of training resulted in significant (P < 0.05) reductions in total cholesterol, glucose, and hemoglobin A1c. A main effect for time was observed in 8ISO, 3NT, and LOOH.

Conclusions: Alterations in metabolic and oxidative stress markers suggest an acute, high-intensity physical stress during WLFF preseason training.