Influence of Personal Protective Equipment on Wildland Firefighters' Physiological Response and Performance during the Pack Test.

The Pack Test (PT) is a widely used test to establish readiness for work in wildland firefighting. It is common to perform this test dressed in regular exercise clothing. However, wildland firefighters (WFF) have to wear personal protective equipment (PPE) during their deployments, which increases the physiological strain and reduces their work capacity. This study aimed to analyse the impact of full PPE on PT performance. Nine male professional WFF performed in random order a PT walking at the fastest possible self-pace wearing two different clothing configurations: (i) traditional short sports gear (SG) and (ii) the PPE currently used by Spanish WFF. Heart rate (HR), rating of perceived exertion and lap time were recorded during the PT. In addition, oxygen uptake (VO) was estimated through the individual VO-HR relationship previously obtained during a graded exercise test. There was a significant decrease in the PT performance (i.e., completion time) (12%, < 0.05) in PPE. The physiological demands with this configuration were significantly higher (10%, < 0.05). WFF spent ~13 min above the anaerobic threshold in PPE vs. ~4 min in SG. A multiple stepwise regression analysis revealed that PT performance variation might be explained by the maximal aerobic velocity (84.5%) in PPE and the VO (75.9%) in SG. In conclusion, wearing complete PPE increases WFF's physiological strain, which translates into a significant PT performance reduction. Performing the test walking at the fastest possible self-pace wearing the PPE would better reflect the high-intensity effort periods reported in real scenarios.