Figure 1.

Schematic representation of the pulmonary oxygen uptake ($\dot{V}$O₂) (panel A) and blood [lactate] responses (panel B) during moderate‐intensity, heavy‐intensity, and severe‐intensity exercise. During moderate‐intensity exercise, $\dot{V}$O₂ and blood [lactate] reach steady‐state values rapidly. During heavy‐ and severe‐intensity exercise, there is an additional oxygen cost (termed $\dot{V}$O₂ slow component) above that expected from the extrapolation of the moderate‐intensity $\dot{V}$O₂‐power output relationship. During heavy‐intensity exercise, the attainment of (higher amplitude) steady‐state values for $\dot{V}$O₂ and blood [lactate] is delayed. The magnitude of the $\dot{V}$O₂ slow component during heavy‐intensity exercise is illustrated by the dotted line provided in panel A. During severe‐intensity exercise, $\dot{V}$O₂ and blood [lactate] continue to rise until $\dot{V}$O₂max (panel A, dashed line) is attained with the limit of tolerance occurring shortly thereafter.