HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 106/5/1553    most recent 91550.2008v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Faisal, A. Articles by Hughson, R. L. Search for Related Content PubMed PubMed Citation Articles by Faisal, A. Articles by Hughson, R. L.

Prior moderate and heavy exercise accelerate oxygen uptake and cardiac output kinetics in endurance athletes

Faculty of Applied Health Sciences, University of Waterloo, Ontario, Canada

Submitted 30 November 2008 ; accepted in final form 25 February 2009

Cardiorespiratory interactions at the onset of dynamic cycling exercise are modified by warm-up exercises. We tested the hypotheses that oxygen uptake (O₂) and cardiac output () kinetics would be accelerated at the onset of heavy and moderate cycling exercise by warm-up. Nine male endurance athletes (peak O₂: 60.5 ± 3.2 ml·min^–1·kg^–1) performed multiple rides of two different 36-min cycling protocols, involving 6-min bouts at moderate and heavy intensities. Breath-by-breath O₂ and beat-by-beat stroke volume (SV) and , estimated by Modelflow from the finger pulse, were measured simultaneously with kinetics quantified from the phase II time constant (₂). One novel finding was that both moderate (M) and heavy (H) warm-up bouts accelerated phase II O₂ kinetics during a subsequent bout of heavy exercise (₂: after M = 22.5 ± 2.7 s, after H = 22.1 ± 2.9 vs. 26.2 ± 3.2 s; P < 0.01). kinetics in heavy exercise were accelerated by both warm-up intensities (₂: M = 22.0 ± 4.1 s, H = 23.8 ± 5.6 s vs. 27.4 ± 7.2 s; P < 0.05). During moderate exercise, prior heavy-intensity warm-up (one or two bouts) accelerated O₂ kinetics and elevated at exercise onset, with no changes in kinetics. A second novel finding was a significant overshoot in the estimate of SV from Modelflow in the first minutes of each moderate and heavy exercise bout. These findings suggest that the acceleration of O₂ kinetics during heavy exercise was enabled by the acceleration of kinetics, and that rapid increases in at the onset of moderate and heavy exercise might result, in part, from an overshoot of SV.

gas exchange; warm-up exercise; arterial-venous oxygen content difference; Finometer Modelflow; acetylene rebreathing

This article has been cited by other articles:

				S. Perrey, M. Burnley, G. P. Millet, F. Borrani, A. M. Jones, D. C. Poole, S. W. Copp, D. M. Hirai, P. Gimenez, T. Busso, et al. Comments on point: counterpoint: the kinetics of oxygen uptake during muscular exercise do/do not manifest time-delayed phase. Modeling concerns. J Appl Physiol, November 1, 2009; 107(5): 1669 - 1670. [Full Text] [PDF]