The purpose of the present study was to elucidate whether oxygen consumption of the respiratory muscles might influence the oxygen supply to the working muscles.
Oxygen consumption of the respiratory muscles and pulmonary resistance were measured in 10 male long distance runners (trained) and 10 sedentary male students (untrained) during bicycle exercise at three submaximal work loads. Oxygen con-sumption of the respiratory muscles was measured by increasing pulmonary ventilation with inhalation of 2% CO₂ in air. Pulmonary resistance was measured with the airway interruption method.
Pulmonary resistance was similar for the trained and untrained subjects. While, oxygen consumption of the respiratory muscles of trained subjects during exercise was, when compared at equal pulmonary ventilation of equal work load (kgm/min or %Vo₂ max), smaller than untrained (p<0.05) .
From the present study it was concluded that the respiratory movements of trained subjects were more efficient than untrained, and that oxygen consumption of the re-spiratory muscles affected the aerobic work capacity more in untrained subjects than in trained.