Lab 10: Non–Exercise-Based Estimation of the Ventilatory Threshold

Theoretically, the ventilatory threshold (VT) is an estimation of the exercise intensity above which anaerobic adenosine triphosphate (ATP) production must supplement aerobic metabolism. Thus, in theory, exercise intensities below the VT are non-fatiguing and are maintained from aerobic ATP production only, while those above the VT are fatiguing and utilize anaerobic plus aerobic ATP production. Typically, the VT occurs at approximately 50 to 60% of maximal oxygen consumption rate (VO₂ max) in untrained to moderately trained individuals, but 80% of VO₂ max or above in highly trained endurance athletes. ⁴