Effect of intervention time on quality and fatigue in paired CPR: a study with lifeguard

Objective: This study compares two rotation strategies during a simulated 16-minute CPR scenario: one with changes every 2 minutes (as recommended by ERC guidelines) and another with self-paced rotations based on perceived fatigue. Methods: Eighteen lifeguards participated in three trials: an individual 2-minute CPR test and two paired 16-minute trials, one with 2-minute rotations and one with self-paced rotations. CPR quality variables (QCPR, QCC, QVR), heart rate (HR), and ratings of perceived exertion (RPE) were assessed. Results: Overall CPR quality was significantly higher in the 2-minute rotationmodel compared to the self-paced approach. Fatigue (HR and RPE) was lower under the standard protocol. However, participants with higher individual test quality sustained longer interventions in the self-paced model. Conclusions: Two-minute rotations ensure higher CPR quality and lower fatigue. Nevertheless, individual capacity predicts performance under self-regulated strategies, suggesting opportunities for personalized approaches in trainingand protocols.