Differences in Workloads of Maximal Tasks in Active-Duty Firefighters

Area of Science:

• Occupational Health
• Exercise Physiology
• Cardiovascular Science

Background:

• Firefighting involves strenuous physical activity with significant cardiovascular demands.
• Assessing firefighter fitness is crucial for job readiness and mitigating health risks.
• Current fitness assessments may not accurately reflect the physiological strain of firefighting tasks.

Purpose of the Study:

• To compare the workload of a maximal treadmill test (TREAD) and a simulated fire suppression task (BURN) in firefighters.
• To examine the relationship between these workloads and firefighter fitness metrics: body mass index (BMI), body fat percentage (BF%), and peak aerobic capacity (VO2PEAK).

Main Methods:

• Workload was quantified using Edward's Training Impulse (ETRIMP) based on time spent in specific heart rate (HR) intensity zones (ZONE1-5).
• Participants underwent both a maximal treadmill test and a simulated fire suppression task.
• Fitness was assessed via BMI, BF%, and VO2PEAK.

Main Results:

• The ETRIMP for the fire suppression task (ETRIMP_BURN) was significantly higher than for the treadmill test (ETRIMP_TREAD).
• Firefighters spent more time in higher HR intensity zones during the fire suppression task.
• Lower BF% and higher VO2PEAK were associated with higher ETRIMP_TREAD but not ETRIMP_BURN. Lower BF% and higher VO2PEAK were linked to less time in the highest HR zone (ZONE5) during BURN.
• BMI was not significantly related to any workload measures.

Conclusions:

• Laboratory-based maximal exercise testing may not adequately simulate the physiological demands of actual firefighting.
• Firefighter readiness assessments should consider the specific demands of the job, as treadmill tests may underestimate workload.
• Less-fit firefighters may experience higher cardiovascular strain during firefighting tasks, necessitating targeted risk reduction strategies.