Computer simulation of exercise hyperpnea.

An analog model which describes the behavior of gas exchange in the lung and of the respiratory control system has been developed to study the physiological mechanisms of exercise hyperpnea. The model consists of three major compartments (lung, brain and tissue) which are connected by circulation. The time delay to reach to the chemoreceptor site and the time constant of the chemoreceptor in response to changes in blood gases are included. Respiration is assumed to be controlled by both neurogenic and humoral factors which act independently and additively. The results showed that the model behavior in terms of steady-state and transient response to exercise and recovery from it was consistent with the experimental observations and suggested that the combination of humoral and neurogenic theory may explain the physiological mechanism of exercise hyperpnea.