Addition of inspiratory resistance increases the amplitude of the slow component of O2 uptake kinetics.
Details
Serval ID
serval:BIB_37628
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Addition of inspiratory resistance increases the amplitude of the slow component of O2 uptake kinetics.
Journal
Journal of Applied Physiology
ISSN
8750-7587 (Print)
ISSN-L
0161-7567
Publication state
Published
Issued date
2003
Peer-reviewed
Oui
Volume
94
Number
6
Pages
2448-2455
Language
english
Abstract
The contribution of respiratory muscle work to the development of the O(2) consumption (Vo(2)) slow component is a point of controversy because it has been shown that the increased ventilation in hypoxia is not associated with a concomitant increase in Vo(2) slow component. The first purpose of this study was thus to test the hypothesis of a direct relationship between respiratory muscle work and Vo(2) slow component by manipulating inspiratory resistance. Because the conditions for a Vo(2) slow component specific to respiratory muscle can be reached during intense exercise, the second purpose was to determine whether respiratory muscles behave like limb muscles during heavy exercise. Ten trained subjects performed two 8-min constant-load heavy cycling exercises with and without a threshold valve in random order. Vo(2) was measured breath by breath by using a fast gas exchange analyzer, and the Vo(2) response was modeled after removal of the cardiodynamic phase by using two monoexponential functions. As anticipated, when total work was slightly increased with loaded inspiratory resistance, slight increases in base Vo(2), the primary phase amplitude, and peak Vo(2) were noted (14.2%, P < 0.01; 3.5%, P > 0.05; and 8.3%, P < 0.01, respectively). The bootstrap method revealed small coefficients of variation for the model parameter, including the slow-component amplitude and delay (15 and 19%, respectively), indicating an accurate determination for this critical parameter. The amplitude of the Vo(2) slow component displayed a 27% increase from 8.1 +/- 3.6 to 10.3 +/- 3.4 ml. min(-1). kg(-1) (P < 0.01) with the addition of inspiratory resistance. Taken together, this increase and the lack of any differences in minute volume and ventilatory parameters between the two experimental conditions suggest the occurrence of a Vo(2) slow component specific to the respiratory muscles in loaded condition.
Keywords
Adult, Airway Resistance, Bicycling, Humans, Inhalation, Kinetics, Male, Models, Biological, Oxygen Consumption, Respiratory Muscles/physiology, Work of Breathing
OAI-PMH
Pubmed
Web of science
Create date
19/11/2007 11:12
Last modification date
20/08/2019 14:25