Respiratory oscillations in arterial carbon dioxide tension as a control signal in exercise.

We have monitored oscillations in arterial pH (of respiratory frequency) in normal man at rest and during exercise. The pH oscillations are known to reflect respiratory oscillations in arterial carbon dioxide tension generated at the lungs. We have found that the pH oscillations increase in their upslope and downslope during exercise. This means that oscillations in arterial carbon dioxide tension can be considered as a control signal.