Running and flying require a substantial increase in energy expenditures and therefore a substantial elevation of respiration. Mammals and birds may have evolved mechanisms to achieve these large increases in breathing with exercise that minimizes the added cost of the breathing itself. The body of a bird is full of air sacs that are used as bellows to move air in and out of their lungs. The muscles and bones that are active and moving during flight may simultaneously assist the movement of air through its respiratory system by expanding and compressing the air sacs. This project will investigate the ways in which the muscular activities of flying and breathing are coordinated. It will provide insights into fundamental questions about the control of breathing in vertebrates, especially during exercise. Comparative studies of different species of birds and of different classes of vertebrates will also address questions about the evolution of the control of breathing during exercise. Such studies are also of value to those interested in human performance and rehabilitation.
