Document Detail


Oxygen uptake, cardiac output and muscle deoxygenation at the onset of moderate and supramaximal exercise in humans.
MedLine Citation:
PMID:  21190035     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
[Formula: see text], [Formula: see text] and muscular deoxyhaemoglobin (HHb) kinetics were determined in 14 healthy male subjects at the onset of constant-load cycling exercise performed at 80% of the ventilatory threshold (80%(VT)) and at 120% of [Formula: see text] (120%(Wmax)). An innovative approach was applied to calculate the time constant (τ(2)) of the primary phase of [Formula: see text] and [Formula: see text] kinetics at 120%(Wmax). Data were linearly interpolated after a semilogarithmic transformation of the difference between required/steady state and measured values. Furthermore, [Formula: see text], [Formula: see text] and HHb data were fitted with traditional exponential models. τ(2) of [Formula: see text] kinetics was longer (62.5 ± 20.9 s) at 120%(Wmax) than at 80%(VT) (27.8 ± 10.4 s). The τ(2) of [Formula: see text] kinetics was unaffected by exercise intensity and, at 120% of [Formula: see text] it was significantly faster (τ(2) = 35.7 ± 28.4 s) than that of [Formula: see text] response. The time delay of HHb kinetics was shorter (4.3 ± 1.7 s) at 120%(Wmax) than at 80%(VT) (8.5 ± 2.6 s) suggesting a larger mismatch between O(2) uptake and delivery at 120%(Wmax). These results suggest that [Formula: see text] at the onset of exercise is not regulated/limited by muscle's O(2) utilisation and that a slower adaptation of capillary perfusion may cause the deceleration of [Formula: see text] kinetics observed during supramaximal exercise.
Authors:
A Adami; S Pogliaghi; G De Roia; C Capelli
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2010-12-29
Journal Detail:
Title:  European journal of applied physiology     Volume:  -     ISSN:  1439-6327     ISO Abbreviation:  -     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-12-30     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Department of Neurological, Neuropsychological, Morphological and Motor Sciences, School of Exercise and Sport Sciences, University of Verona, Via Felice Casorati, 43, 37131, Verona, Italy.
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