Effects of Environmental Heat and Antioxidant Ingestion on Blood Markers of Oxidative Stress in Professional Firefighters Performing Structural Fire Exercises

Objective: Firefighters (FFs) involved in fire suppression have the greatest on-duty risk of cardiovascular disease (CVD), which may be caused by oxidative stress (OS). Methods: Healthy, active FFs performed a victim "search and clear" exercise involving three conditions: (1) no heat, (2) heat + antioxidant, and (3) heat + placebo. Blood samples were analyzed for OS markers glutathione (GSH), oxidized glutathione (GSSG), superoxide dismutase (SOD), catalase (CAT), and advanced oxidation protein products (AOPP). Results: Increased GSH was found during both heat conditions compared with no heat. CAT activity was higher immediately post exercise. AOPP was reduced post exercise. Conclusions: Antioxidant supplementation did not impact the OS response to exercise. Added heat did not cause OS and exercise resulted in reductions in OS markers. These findings can be attributed to the training status of the FFs involved.