Sodium bicarbonate ingestion alters the slow but not the fast phase of V̇O2 kinetics

Hdl Handle:
http://hdl.handle.net/10149/96905
Title:
Sodium bicarbonate ingestion alters the slow but not the fast phase of V̇O2 kinetics
Authors:
Berger, N. J. A. (Nicolas); Mcnaughton, L. R.; Keatley, S.; Wilkerson, D. P. (Daryl); Jones, A. M. (Andrew)
Affiliation:
Manchester Metropolitan University. Department of Exercise and Sport Science.
Citation:
Berger, N. J. A. et. al. (2006) 'Sodium bicarbonate ingestion alters the slow but not the fast phase of V̇O2 kinetics', Medicine & Science in Sports & Exercise, 38 (11), pp.1909-1917.
Publisher:
American College of Sports Medicine
Journal:
Medicine & Science in Sports & Exercise
Issue Date:
Nov-2006
URI:
http://hdl.handle.net/10149/96905
DOI:
10.1249/01.mss.0000233791.85916.33
Abstract:
Purpose: The influence of metabolic alkalosis (ALK) on pulmonary O 2 uptake (pV̇O2) kinetics during high-intensity cycle exercise is controversial. The purpose of this study was to examine the influence of ALK induced by sodium bicarbonate (NaHCO3) ingestion on pV̇O2 kinetics, using a sufficient number of repeat-step transitions to provide high confidence in the results obtained. Methods: Seven healthy males completed step tests to a work rate requiring 80% pV̇O 2max on six separate occasions: three times after ingestion of 0.3 g·kg-1 body mass NaHCO3 in 1 L of fluid, and three times after ingestion of a placebo (CON). Blood samples were taken to assess changes in acid-base balance, and pV̇O2 was measured breath-by-breath. Results: NaHCO3 ingestion significantly increased blood pH and [bicarbonate] both before and during exercise relative to the control condition (P < 0.001). The time constant of the phase II pV̇O2 response was not different between conditions (CON: 29 ± 6 vs ALK: 32 ± 7 s; P = 0.21). However, the onset of the pV̇O2 slow component was delayed by NaHCO3 ingestion (CON: 120 ± 19 vs ALK: 147 ± 34 s; P < 0.01), resulting in a significantly reduced end-exercise pV̇O2 (CON: 2.88 ± 0.19 vs ALK: 2.79 ± 0.23 L-min-1; P < 0.05). Conclusions: Metabolic alkalosis has no effect on phase II pV̇O2 kinetics but alters the pV̇O2 slow-component response, possibly as a result of the effects of NaHCO3 ingestion on muscle pH.
Type:
Article
Language:
en
Keywords:
metabolic alkalosis; O2 dynamics; phase II time constant; pulmonary gas exchange; VO2 slow component
ISSN:
0195-9131
Rights:
Author can archive post-print (ie final draft post-refereeing). For full details see http://www.sherpa.ac.uk/romeo/ [Accessed 20/04/2010]
Citation Count:
4 [Scopus, 20/04/2010]

Full metadata record

DC FieldValue Language
dc.contributor.authorBerger, N. J. A. (Nicolas)en
dc.contributor.authorMcnaughton, L. R.en
dc.contributor.authorKeatley, S.en
dc.contributor.authorWilkerson, D. P. (Daryl)en
dc.contributor.authorJones, A. M. (Andrew)en
dc.date.accessioned2010-04-20T12:38:33Z-
dc.date.available2010-04-20T12:38:33Z-
dc.date.issued2006-11-
dc.identifier.citationMedicine & Science in Sports & Exercise; 38 (11): 1909-1917en
dc.identifier.issn0195-9131-
dc.identifier.doi10.1249/01.mss.0000233791.85916.33-
dc.identifier.urihttp://hdl.handle.net/10149/96905-
dc.description.abstractPurpose: The influence of metabolic alkalosis (ALK) on pulmonary O 2 uptake (pV̇O2) kinetics during high-intensity cycle exercise is controversial. The purpose of this study was to examine the influence of ALK induced by sodium bicarbonate (NaHCO3) ingestion on pV̇O2 kinetics, using a sufficient number of repeat-step transitions to provide high confidence in the results obtained. Methods: Seven healthy males completed step tests to a work rate requiring 80% pV̇O 2max on six separate occasions: three times after ingestion of 0.3 g·kg-1 body mass NaHCO3 in 1 L of fluid, and three times after ingestion of a placebo (CON). Blood samples were taken to assess changes in acid-base balance, and pV̇O2 was measured breath-by-breath. Results: NaHCO3 ingestion significantly increased blood pH and [bicarbonate] both before and during exercise relative to the control condition (P < 0.001). The time constant of the phase II pV̇O2 response was not different between conditions (CON: 29 ± 6 vs ALK: 32 ± 7 s; P = 0.21). However, the onset of the pV̇O2 slow component was delayed by NaHCO3 ingestion (CON: 120 ± 19 vs ALK: 147 ± 34 s; P < 0.01), resulting in a significantly reduced end-exercise pV̇O2 (CON: 2.88 ± 0.19 vs ALK: 2.79 ± 0.23 L-min-1; P < 0.05). Conclusions: Metabolic alkalosis has no effect on phase II pV̇O2 kinetics but alters the pV̇O2 slow-component response, possibly as a result of the effects of NaHCO3 ingestion on muscle pH.en
dc.language.isoenen
dc.publisherAmerican College of Sports Medicineen
dc.rightsAuthor can archive post-print (ie final draft post-refereeing). For full details see http://www.sherpa.ac.uk/romeo/ [Accessed 20/04/2010]en
dc.subjectmetabolic alkalosisen
dc.subjectO2 dynamicsen
dc.subjectphase II time constanten
dc.subjectpulmonary gas exchangeen
dc.subjectVO2 slow componenten
dc.titleSodium bicarbonate ingestion alters the slow but not the fast phase of V̇O2 kineticsen
dc.typeArticleen
dc.contributor.departmentManchester Metropolitan University. Department of Exercise and Sport Science.en
dc.identifier.journalMedicine & Science in Sports & Exerciseen
ref.citationcount4 [Scopus, 20/04/2010]en
or.citation.harvardBerger, N. J. A. et. al. (2006) 'Sodium bicarbonate ingestion alters the slow but not the fast phase of V̇O2 kinetics', Medicine & Science in Sports & Exercise, 38 (11), pp.1909-1917.-
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