Tactical populations face increased risk on the job, and it is known that firefighters have high levels of cardiac-related death. Aerobic fitness is a modifiable cardiac risk factor, but many fire stations lack the proper equipment to easily assess aerobic fitness levels of their firefighters. Additionally, many fire stations lack wellness programs to hold firefighters accountable for maintaining their fitness levels.
Purpose: We assessed the validity of the submaximal 6-minute walk test (6MWT) as a measure of aerobic capacity compared to a maximal treadmill test and the submaximal Gerkin protocol.
Methods: Twenty-four firefighters (19 male, 5 female, 34.8 ± 9.7 years; 38.1 ± 3.6 kg·m-2) completed the 6MWT, the submaximal Gerkin protocol, and a maximal treadmill test. Data were analyzed with Bland-Altman plots and correlation analysis.
Results: We found equivalence between the 6MWT and directly measured VO2max and between the 6MWT and Gerkin protocol using Bland-Altman plots. In our cohort, the 6MWT underestimated VO2max (31.57 ml·kg-1·min-1) compared to directly measured VO2max (38.1 ml·kg-1·min-1) by 17% and to the Gerkin (40.48 ml·kg-1·min-1) by 22%.
Conclusion: Considering its equivalence, using the 6MWT could be a more accessible way to quantify aerobic capacity in firefighters. Despite underestimation, having an easy to administer protocol may encourage more fire stations to assess pre- and post- fitness levels regularly.
Keywords: Firefighter; aerobic capacity; fitness assessment; maximal fitness; submaximal fitness.