AUTHOR=Zhang Xinxin , Li Chengxiu , Zhou Yong , Liu Weiguo 
  
TITLE=Oxygen consumption efficiency in firefighters: roles of fatigue and rescue task
  
JOURNAL=Frontiers in Physiology
  
VOLUME=Volume 16 - 2025
  
YEAR=2025
  
URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2025.1708050
  
DOI=10.3389/fphys.2025.1708050
  
ISSN=1664-042X
  
ABSTRACT=ObjectiveThis study compared standardized oxygen consumption responses during rescue tasks with varying loads and methods across different fatigue states in firefighters to identify optimal rescue strategies and enhance operational efficiency.MethodsSixty-three professional healthy male firefighters were recruited. Oxygen consumption was measured using a wearable metabolic system as they performed 5 × 20-m shuttle sprints with different task loads (10 kg, 20 kg, 30 kg) and rescue methods (shoulder-, cradle-, hand-carrying) under five fatigue states (non-fatigue, whole-body, and mild/moderate/severe knee fatigue).ResultsA mixed-model ANOVA revealed a significant main effect of task load on standardized oxygen consumption (F = 620.61, P < 0.001, ƞp2 = 0.798). Post-hoc tests showed that standardized oxygen consumption was significantly lower during medium-load (2.464 ± 0.616 mL/min/kg2) and large-load tasks (1.615 ± 0.317 mL/min/kg2) compared to small-load tasks (4.718 ± 1.043 mL/min/kg2) (all P < 0.05). Consumption during large-load tasks was also significantly lower than during medium-load tasks (P < 0.05). The main effects of fatigue states and rescue methods were not significant.ConclusionTask load is the primary factor influencing oxygen efficiency during high-intensity shuttle sprints. Large-load tasks resulted in significantly lower standardized oxygen consumption across all fatigue states and rescue methods, indicating a “small load-low efficiency” phenomenon. Prioritizing large-load (30 kg) tasks in time-critical emergencies may improve rescue efficiency.