Figure 5: Breathing matches metabolic rate, but with subtle deficits, after carotid chemoreceptor denervation in Man. 5–11 controls at 70% ( Wew) or 150% ( Wew) anaerobic (lactic acidosis) threshold and 5-6 carotid denervated subjects at 70% ( Wew) or 150% ( Wew) anaerobic threshold during constant load bicycle ergometry. (a) Mean ± se pH and PaCO2 in controls (open circle with filled line) and denervated (filled circle with dashed line). Mean resting PaCO2 in controls was mmHg and in denervated was mmHg. (b) Mean ± se minute ventilation per metabolic rate (/). ns , *versus 70% anaerobic threshold value for that condition. (c) Normalized minute ventilation as a percentage of total change in controls (open circle with filled line) and denervated (filled circle with dashed line) plotted against mean ± se minutes of exercise. (d) Average minute ventilation for percent of maximal for 1 min incremental cycle ergometer work test for 11 control and 6 denervated subjects. Vertical bars at each point are ± 1 se m. (e) PaCO2, bicarbonate , and pH changes in normal (top) and denervated (bottom) subjects at 0 Watts (filled circles) and at terminal () work rates for studies described above. Dashed arrows are averages for each group. Diagonal dashed lines are pH isopleths for -pCO2 buffer system. Reproduced with permission from Wasserman et al. .