The profile of human oxygen consumption during high power exercise has captivated exercise physiologists for decades and the mechanism behind the slow component of this profile is still unclear [1-4]. The present study models this component from a thermodynamics perspective that considers the work associated with gas pressure, volume and temperature changes for the glucose-based equation of respiration. Model slow component curves closely match clinically measured curves [2,4,7] in shape and scale. Existing proposed mechanisms for the slow component are generally more qualitative or physiological in nature. Thus, the presented model may represent a significant contributing mechanism towards the slow component.