New nine-panel plot. This is the same test as Figure 2. The panel numbers refer to their original position in Figure 2. This new format was first announced in . Ve = minute volume, VO2 = oxygen uptake, HR = heart rate, VCO2 = carbon dioxide output, Vt = tidal volume, RER = respiratory exchange ratio, PETO2 = partial pressure end-tidal oxygen, PETCO2 = partial pressure end-tidal carbon dioxide. Data from author’s laboratory.