Physical activity level and cardiovascular strain in wildland firefighters during forest fire suppression: an exploratory study

Abstract Introduction: wildland fire suppression exposes firefighters to high cardiovascular risk. Objective: to evaluate the physical activity level (PAL), sedentary behavior (SB) and cardiovascular strain of wildland firefighters during a large fire suppression. Methods: for 9 days, 24h/day, we evaluated 7 male wildland firefighters. Participants had their heart rate (HR) measured every second and physical activity recorded by an accelerometer sensor every 60 seconds. The mean records of the 2nd, 3rd and 4th days of fire suppression were computed for the analysis. PAL was evaluated by the vector magnitude and cardiovascular strain by HR intensity. Results: the volunteers spent on average 112 (SD 24) min/day in moderate to vigorous physical activity (MVPA), achieved 14,803 (SD 1,667) steps/day and spent 1,860 (SD 481) kcal/day. Cardiovascular strain remained on average at 47 (SD 42) min/day of vigorous effort and 8 (SD 12) min/day of very vigorous physical activity. Conclusion: the firefighters evaluated during a large-scale wildland fire suppression accounted for more than double of the minimum recommended MVPA/week in three days, showed more than 50 min/day of high cardiovascular strain, and little time on sedentary behavior compared to other professions.