We have determined whether changes in PCO2 above and below eucapnia modulate the precision of the voluntary control of breathing. Twelve trained subjects performed a compensatory tracking task in which they had to maintain the position of a cursor (perturbed by a variable triangular forcing function) on a fixed target by breathing in and out of a spirometer (ventilatory tracking; at 10 l/min). Before each task, subjects hyperventilated for 5 min, and the end-tidal PCO2 (PET(CO2)) was controlled; tracking was then performed separately at hypocapnia, eucapnia, and hypercapnia (PET(CO2) ~25, 37, and 43 Torr, respectively). Ventilatory tracking error was unchanged during hypocapnia (P > 0.05) but was significantly worse during hypercapnia (P <0.003), compared with eucapnia; arm tracking error, performed as a control, was not significantly affected by PET(CO2) (P > 0.05). In conclusion, ventilatory tracking performance is unaffected by the eucapnic PCO2. From this, we suggest that resting breathing in awake humans may be independent of chemical drives and of the prevailing PCO2.
|Number of pages||7|
|Journal||Journal of Applied Physiology|
|Publication status||Published - Nov 1999|
- Carbon dioxide
- Voluntary control of movement