Titre
Effect of inspiratory threshold loading on ventilatory kinetics during constant-load exercise.
Type
article
Institution
Externe
Auteur(s)
Keslacy, S.
Auteure/Auteur
Matecki, S.
Auteure/Auteur
Carra, J.
Auteure/Auteur
Borrani, F.
Auteure/Auteur
Candau, R.
Auteure/Auteur
Prefaut, C.
Auteure/Auteur
Ramonatxo, M.
Auteure/Auteur
Liens vers les personnes
ISSN
0363-6119
Statut éditorial
Publié
Date de publication
2005
Volume
289
Numéro
6
Première page
R1618
Dernière page/numéro d’article
R1624
Peer-reviewed
Oui
Langue
anglais
Résumé
Humoral factors play an important role in the control of exercise hyperpnea. The role of neuromechanical ventilatory factors, however, is still being investigated. We tested the hypothesis that the afferents of the thoracopulmonary system, and consequently of the neuromechanical ventilatory loop, have an influence on the kinetics of oxygen consumption (VO2), carbon dioxide output (VCO2), and ventilation (VE) during moderate intensity exercise. We did this by comparing the ventilatory time constants (tau) of exercise with and without an inspiratory load. Fourteen healthy, trained men (age 22.6 +/- 3.2 yr) performed a continuous incremental cycle exercise test to determine maximal oxygen uptake (VO2max = 55.2 +/- 5.8 ml x min(-1) x kg(-1)). On another day, after unloaded warm-up they performed randomized constant-load tests at 40% of their VO2max for 8 min, one with and the other without an inspiratory threshold load of 15 cmH2O. Ventilatory variables were obtained breath by breath. Phase 2 ventilatory kinetics (VO2, VCO2, and VE) could be described in all cases by a monoexponential function. The bootstrap method revealed small coefficients of variation for the model parameters, indicating an accurate determination for all parameters. Paired Student's t-tests showed that the addition of the inspiratory resistance significantly increased the tau during phase 2 of VO2 (43.1 +/- 8.6 vs. 60.9 +/- 14.1 s; P < 0.001), VCO2 (60.3 +/- 17.6 vs. 84.5 +/- 18.1 s; P < 0.001) and VE (59.4 +/- 16.1 vs. 85.9 +/- 17.1 s; P < 0.001). The average rise in tau was 41.3% for VO2, 40.1% for VCO2, and 44.6% for VE. The tau changes indicated that neuromechanical ventilatory factors play a role in the ventilatory response to moderate exercise.
PID Serval
serval:BIB_37621
PMID
Date de création
2007-11-19T09:12:37.490Z
Date de création dans IRIS
2025-05-20T16:25:47Z