Baylie G. Sigmund1, Halle N. Brin1, Emily K. Hanenberg1, Cami L. Roy1, Nathan D. Dicks2, David J. Miller1, Michael J. Carper1, Allison M. Barry1

1 Pittsburg State University, Pittsburg, KS; 2 Concordia College, Moorhead, MN

There is an increased risk of critical cardiorespiratory (CR) events in firefighters while on-duty due to poor overall fitness levels. The Restrictive Breathing Apparatus (RBA) is an adaptive training tool utilized by firefighters to simulate the restrictive tendencies of the self-contained breathing apparatus (SCBA). Wearing the RBA while completing task-specific training has the potential to increase fitness levels, which may lead to more efficient and productive on-duty tasks. PURPOSE: The purpose of this study was to investigate the effect of the RBA on cardiorespiratory function in college-age subjects. METHODS: College students (n=16) volunteered to participate in this study. Briefly, a modified Balke-Ware protocol was used in conjunction with a physical activity rating (PA-R) scale to determine the speed and incline of the stage graded exercise test (GXT). The test consisted of a 3-min warm-up, a GXT, an active recovery stage, and a square-wave verification bout. The PA-R scale was used to individualize the GXT. Each student completed a control (CON) GXT with a square-wave verification bout with no RBA and a single bout GXT with no verification bout while wearing the RBA to determine maximal oxygen uptake (VO2max). The RBA was adapted to fit the two-way breathing valve. There was no randomization of tests. Participants started with the CON then RBA. There was a minimum of 48 hours and a maximum of 7 days between each test. A comparison between CON and RBA VO2max was assessed using a dependent t-test in SPSS (v.26). The level of significance was set at p<0.05. RESULTS: Thirteen participants (Males = 5; Age: 22.2 ± 1.4 yrs; BMI: 26.8 ± 5.3 kg/m2; Percent Body Fat: 26.3 ± 6.2); completed the study. There was a significant difference between CON VO2max and the RBA (t(12)=11.3, p<0.001, d=3.1; 34.0 ± 4.7 and 21.4 ± 5.1 ml/kg/min, respectively). CONCLUSION: Previous research suggests the SCBA reduces VO2max by 10-15%, although this study presents evidence that the RBA reduces VO2max by ~37%. Therefore, future research should investigate apparatuses for training firefighters that employ less restriction of the cardiorespiratory system.

ACKNOWLEDGEMENTS: This project was supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Number P20 GM103418. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

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