Ventilatory response to hypercapnia before and after athletic training

To assess the effect of athletic training on the slope (S) of the hypercapnic ventilatory response at rest, we prospectively studied 13 untrained young men. S was determined by the slope of the regression delta VI/delta PETCO2, calculated between 48 and 63 mm Hg during CO2 rebreathing. Six of the subjects trained for seven months as intercollegiate rowers while the remaining subjects underwent no training and served as controls. After training, the rowers had a significant increase in S during hypercapnia. No such change was seen in the untrained controls. These data suggest that athletic training in normal subjects increases CO2 sensitivity at rest.