Optimality Principle in Respiratory Control

A classical dilemma in the physiological control of human respiration is that the increase in respiratory ventilation during muscular exercise is normally sustained despite little increase in the intensities of chemical stimulation to breathing. To account for this phenomenon, it has recently been suggested that the control law governing the ventilatory output may be an optimization rather than reflex process; the response in effect being set by the balance between the chemical drive to breathe and the natural tendency to reduce the work of breathing (Poon, C.S., in Modelling and Control of Breathing, Elsevier, 1983). The purpose of this paper is to extend the previous approach to include a general analysis of both respiratory ventilation and pattern responses to CO2 inhalation and exercise. The results suggest that, under the optimality hypothesis, a consistent prediction of all respiratory responses is possible.