Quinn & Coons 2011, The talk test and thresholds

Study of the talk test against the ventilatory and lactate thresholds. The point at which speaking becomes uncomfortable falls in the threshold region (the last comfortable-speech stage sat near 64% of VO₂max and aligned more closely with the lactate threshold), making the talk test a usable field anchor for easy versus hard effort, though with wide limits of agreement. Moderate.