Ventilation at Transition from Rest to Exercise

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Abstract
Asmussen., E. Ventilation at transition from rest to exercise. Acta physiol. scand. 1973. 89. 68–78.The “fast neurogenic component” of the increase in ventilation taking place at the transition from rest to exercise was studied by a breath‐to‐breath analysis of VE. AND PACO2 The questions investigated were: 1) Is the “fast neurogenic component” correlated to the intensity of the exercise: 2) Is it due to a specific work stimulus to the respiratory center, or caused by an increased sensitivity to existing chemical stimuli? 3) Is it related to movements or to the mechanical tensions in the working muscles? The results showed: 1) There is a rough correlation between the “fast neurogenic component” and the power of the bicycle‐work performed. 2) If the chemical stimuli, expressed by PACO2 AND PAo2, are eliminated by voluntary hyperventilation in pure oxygen, the “fast neurogenic component” disappears. With one or both of these stimuli present, exercise augments their effect. 3) Transition from rest to static exercise (no movements) is not accompanied by a “fast neurogenic component”. Rhythmic movements cause a rapid increase in VE, related to the frequency of movement. Sudden loacling of the bicycle during no‐load pedalling causes a relatively slower further increase in ventilation, apparently independent of the force exerted on the pedals, but related to the power of work. It is suggested that some metabolic factor in the working muscles is responsible for this part of the “fast neurogenic component”.