Cardiac Efficiency as a Potential Marker of Firefighter Expertise: A Pilot Study of Heart Rate Variability Monitoring in Realistic Search-and-Rescue Training

Expertise in high-stakes occupations is typically evaluated through performance outcomes, potentially neglecting physiological efficiency-a dimension critical for career longevity in physically demanding work. In this pilot study, we investigated whether expert firefighters achieve comparable task performance with lower cardiovascular activation and faster autonomic recovery than novices during realistic search-and-rescue operations. Twenty-two male firefighters completed navigation tasks in a high-fidelity training facility under operational conditions (complete darkness, full protective equipment). Using a 2 × 2 quasi-experimental design, we manipulated navigation strategies (route-based vs. survey-based) and continuously recorded heart rate variability across baseline, execution, and recovery periods. Our preliminary data suggest that behavioral outcomes and physiological responses may be largely decoupled in this context. Experts and novices demonstrated equivalent task completion times and accuracy. However, experts exhibited substantially lower heart rate elevation during tasks and 46% greater parasympathetic recovery post-task. Critically, an expertise-by-strategy interaction suggested that experts' efficiency advantages were magnified when employing route-based strategies aligned with training protocols, whereas novices showed no strategy-dependent differences. These findings provide preliminary evidence that physiological efficiency represents a distinct expertise component, suggesting that identical overt performance can mask vastly different internal costs. Heart rate variability monitoring may therefore serve as a useful exploratory tool to help identify individuals requiring additional skill consolidation or recovery support before overt performance degrades.