# Differences in Workloads of Maximal Tasks in Active-Duty Firefighters

## TL;DR

This study compares the physical workload of a treadmill test and a simulated fire suppression task in firefighters, finding that the treadmill test does not reflect the intensity of real firefighting work.

## Contribution

The study introduces a new method to quantify workload using heart rate zones and shows that treadmill testing may not reflect real firefighting demands.

## Key findings

- The fire suppression task had a higher workload than the treadmill test.
- Less-fit firefighters spent more time in high-intensity heart rate zones during the fire suppression task.
- Body fat percentage and aerobic capacity were related to treadmill workload but not to fire suppression workload.

## Abstract

The purpose of this study was to compare the workload of a maximal treadmill test (TREAD) and a fire suppression task (BURN) in firefighters and to examine their relationships to fitness as measured by body mass index (BMI), percent body fat (BF%), and peak aerobic capacity (VO2PEAK). The amount of time spent in the heart rate (HR) intensity ranges of 50–59% HRMAX (ZONE1), 60–69% HRMAX (ZONE2), 70–79% HRMAX (ZONE3), 80–89% HRMAX (ZONE4), and ≥90% HRMAX (ZONE5) quantified the workload as the Edward’s Training Impulse for TREAD (ETRIMPTREAD) and BURN (ETRIMPBURN). The ETRIMPTREAD was significantly less than ETRIMPBURN. For TREAD, ZONE5 > ZONE2 and ZONE3. For BURN, ZONE4 > ZONE1, ZONE2, and ZONE5 > ZONE1, ZONE2, and ZONE3. A lower BF% and greater VO2PEAK were related to a greater ETRIMPTREAD and unrelated to ETRIMPBURN. For BURN only, a lower BF% and greater VO2PEAK were related to less time in ZONE5. BMI was unrelated to all workload measures. Laboratory-based maximal exercise testing does not adequately reflect the workload of simulated fire suppression and therefore may not be indicative of firefighter readiness to meet job demands. Less-fit firefighters rely on higher cardiovascular intensities to complete the same workload, and practitioners should consider this when selecting strategies to reduce job-associated cardiovascular risk.