Figure 2.

Graphs showing the rate of oxygen consumption during symptom-limited incremental cardiopulmonary cycle exercise testing at the ventilatory threshold measured in the Canadian Cohort Obstructive Lung Disease study participants and predicted using reference equations published by Jones et al¹⁰ in 1985. Jones et al^a reference equations are based on participant height and age, whereas Jones et al^b reference equations additionally include participant body mass.