Optimal control of respiration in exercise

A two-level hierarchical control system is presented to control the respiratory frequency, the dead space and the expiratory reserve volume in exercise. In the first control stage, the criterion of minimum average respiratory work rate is used to determine the optimal values of respiratory frequency. The input to this controller is the ventilatory demand. In the second stage of control, the hypothesis of equalization of maximal inspiratory and expiratory pressures is used to determine the lung's midposition. This optimal procedure has been applied by using a rectangular airflow pattern. The theoretical results have been found to be in good agreement with the experimental data in low and moderate exercise.