Study of energy expenditure (oxygen consumption, EPOC, and lactate) for different running distances

Introduction: This study addressed the metabolic demands of running by analyzing the contributions of oxygen consumption during exercise, excess post-exercise oxygen consumption (EPOC), and lactate accumulation to total energy expenditure. Understanding the interaction between these components is essential for optimizing training strategies and improving physiological monitoring in elite athletes. Objective: To evaluate the relative contributions of aerobic and anaerobic energy systems across different running distances using a validated physiological approach in elite-level male runners. Methodology: The study involved sixteen elite male runners from Nineveh, Iraq, who completed 100-meter, 400-meter, and 3000-meter running trials under controlled environmental conditions. Metabolic data were collected using a portable gas analyzer, while lactate concentrations were assessed via capillary blood sampling. Results: The results revealed significant differences in energy expenditure components across the running distances (p < 0.001). During the 100-meter sprint, anaerobic metabolism dominated, with oxygen consumption accounting for 8.57%, EPOC 68.87%, and lactate 22.56%. In the 400-meter trial, energy contributions were more balanced, with 16.78% from oxygen, 53.04% from EPOC, and 30.17% from lactate. The 3000-meter run was characterized by aerobic dominance, with oxygen contributing 68.00%, EPOC 25.96%, and lactate 6.04%. Statistical tests confirmed the significant role of anaerobic metabolism in short-duration efforts. Discussion: The discussion emphasized that earlier studies often underestimated anaerobic contributions. Incorporating lactate kinetics and EPOC provides a more complete understanding of energy demands during intense exercise. Conclusions: It is concluded that integrating anaerobic components yields a more accurate estimation of total energy expenditure, supporting improved performance modeling and health-oriented interventions.