Exercise Physiology: Theory and Application to Fitness and Performance 9th Edition by Scott Powers, Edward Howley

Exercise 8

Graph the ventilatory response in the transition from rest to constant-load submaximal exercise. What happens to ventilation if the exercise is prolonged and performed in a hot/humid environment? Why?

Step 1 of 2

During a transition from rest to constant load submaximal exercise, changes occur in the pulmonary ventilation. At the beginning of the exercise, expired ventilation (V_E) increases rapidly. It then becomes slower and reaches a steady-state. These changes are shown in graph 1 given below.

The arterial tensions of PCO₂ and PO₂ are relatively unchanged during the submaximal exercise. However, the arterial PO₂ decreases and arterial PCO₂ slightly increases in the transition from rest to steady-state exercise, as shown in graph 1.

Graph 1: Changes in ventilation and partial pressures of O2 and CO2 n the transition from rest to steady-state submaximal exercise.