Effect of epinephrine on slow component of oxygen consumption during heavy exercise

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dc.contributor.advisor Smith, H en
dc.contributor.author Villamonte, Romina en
dc.date.accessioned 2013-03-17T19:07:45Z en
dc.date.issued 2013 en
dc.identifier.uri http://hdl.handle.net/2292/20284 en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract Prior heavy exercise bout on cycle ergometer changes the V O2 kinetics of a subsequent heavy exercise bout. These changes are an increase in V O2 fundamental component (Ap) and a reduction in V O2 slow component (V O2sc) without changing primary component time constant. Infusion of epinephrine has shown to increase resting V O2 levels in humans at rest and during exercise. To test the effect of epinephrine on V O2 kinetics, epinephrine was injected at the beginning of exercise and the kinetics of oxygen consumption was compared with the oxygen kinetics of a prior and second exercise bouts. Seven healthy physically active male participants volunteered for the study. Participants performed 8 min bout of heavy exercise on an electrically braked cycle ergometer preceded by 1) 8 min heavy exercise bout with a 6 min rest period in between and 2) 0.10 mg epinephrine intra muscular injection on deltoid immediately followed by 5 minutes rest to reach it’s onset of action. Same protocol was performed in two different days. Bloods samples to measure plasma [Epi] and [NE] were taken ten times in total during each testing day. Fundamental amplitude (Ap) of epinephrine bout was significantly higher than the prior cycling bout (p < 0.05). Slow component of oxygen uptake (As’) was significantly lower in the second cycling bout (222 + 77.4 mlO2*min-1) compared to the prior cycling bout (369.4 + 135.4 mlO2*min-1;p < 0.05) and to epinephrine cycling bout (357.1 + 178.6 mlO2*min-1; p = 0.05). [Epi] at end of epinephrine bout was significantly higher when compared to blood samples taken, pre-prior, 2-min into prior, pre-second, 2-min into second and pre-Epi injection (p < 0.05). The results of the study demonstrate that epinephrine injection increased magnitude of Ap and V O2end compared to prior heavy bout. However, it had no effect on V O2 baseline, effective time constant, or V O2sc compared to prior heavy bout. No significance differences were found in V O2 kinetics when comparing second heavy bout and epinephrine injection heavy bout. Results show that the increase in [Epi] may be responsible in part for the changes seen in V O2 kinetics of second heavy exercise bout. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/nz/ en
dc.title Effect of epinephrine on slow component of oxygen consumption during heavy exercise en
dc.type Thesis en
thesis.degree.grantor The University of Auckland en
thesis.degree.level Masters en
dc.rights.holder Copyright: The Author en
pubs.elements-id 374365 en
pubs.record-created-at-source-date 2013-03-18 en

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