Firefighter's personal protective equipment and the chronotropic index

Abstract

The purpose of this study was to investigate the effects of personal protective equipment (PPE) on cardiovascular and metabolic responses during incremental exercise, and to determine if PPE affects the relationship between heart rate (HR) and oxygen uptake when expressed as the chronotropic index (CI). Ten male participants performed graded exercise tests under three conditions: control (CON), (PPE) and weighted vest (WV) (same weight as PPE). Time to exhaustion was significantly longer in the CON compared to the other conditions (p < 0.01). Submaximal oxygen uptake and HR were significantly lower in the CON compared to the PPE and WV conditions. The CI (CON, 32.2 ± 4.5; PPE, 31.7 ± 5.7; WV, 32.6 ± 4.9) was similar in all three conditions. This study has shown that additional weight and encapsulating clothing leads to elevations in HR and oxygen uptake compared to a control condition, however, the CI remains unaffected.

Practitioner Summary: Firefighters wear personal protective equipment that is designed to protect the wearer; however it also imposes a physiological burden. It is known that work in firefighting PPE increases cardiovascular and metabolic strain. This study has shown that PPE does not alter the relationship between heart rate and oxygen uptake.

Keywords:

• firefighting
• personal protective equipment
• heart rate
• oxygen uptake
• chronotropic index

Acknowledgements

The research presented in this paper was performed as part of the UCLA PHASER Program, sponsored by the Department of Homeland Security Science and Technology Directorate. We wish to express our thanks and appreciation to the Program Manager, Jalal Mapar, and all the members of the PHASER research group, especially William Kaiser, Maxim Batalin, Brett Dolezal, and Jeannie Haller for their support during this research project. We are also appreciative of the willingness of participants to give so generously of their time to support this work.