Determinants and control of breathing during muscular exercise.

Introduction Exercise hyperpnoea is considered to be one of the major remaining challenges to understanding the control of human systemic function. The topic is currently in an exciting phase, both with respect to novel perspectives on its control and the application of novel techniques to investigate previously proposed mechanisms. However, despite this, the integrative aspects of the control that so closely regulates arterial PCO2 (PaCO2) and pH (pHa) during moderate exercise, and which constrains the fall in pHa at higher work rates, seem no less elusive. We attempt in this review to provide a current perspective on the mechanisms proposed to contribute to the exercise hyperpnoea in humans (typically under laboratory conditions) using, as a frame of reference, the diVerent regulatory demands of the diVerent temporal and intensity domains.