Document Detail

The intracellular to extracellular proton gradient following maximal whole body exercise and its implication for anaerobic energy production.
MedLine Citation:
PMID:  20379830     Owner:  NLM     Status:  MEDLINE    
Maximal exercise elicits systemic acidosis where venous pH can drop to 6.74 and here we assessed how much lower the intracellular value (pH(i)) might be. The wrist flexor muscles are intensively involved in rowing and (31)P-magnetic resonance spectroscopy allows for calculation of forearm pH(i) and energy metabolites at high time resolution. Arm venous blood was collected in seven competitive rowers (4 males; 72 +/- 5 kg; mean +/- SD) at rest and immediately after a "2,000 m" maximal rowing ergometer effort when hemoglobin O(2) saturation decreased from 51 +/- 4 to 29 +/- 9% and lactate rose from 1.0 +/- 0.1 to 16.8 +/- 3.6 mM. Venous pH and pH(i) decreased from 7.43 +/- 0.01 to 6.90 +/- 0.01 and from 7.05 +/- 0.02 to 6.32 +/- 0.19 (P < 0.05), respectively, while the ratio of inorganic phosphate to phosphocreatine increased from 0.12 +/- 0.03 to 1.50 +/- 0.49 (P < 0.05). The implication of the recorded intravascular and intracellular acidosis and the decrease in PCr is that the anaerobic contribution to energy metabolism during maximal rowing corresponds to 4.47 +/- 1.8 L O(2), a value similar to that defined as the "accumulated oxygen deficit". In conclusion, during maximal rowing the intracellular acidosis, expressed as proton concentration, surpasses approximately 4-fold the intravascular acidosis, while the resting gradient is approximately 2.
Stefanos Volianitis; N H Secher; B Quistorff
Publication Detail:
Type:  Journal Article     Date:  2010-04-09
Journal Detail:
Title:  European journal of applied physiology     Volume:  109     ISSN:  1439-6327     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-07-23     Completed Date:  2010-11-26     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  1171-7     Citation Subset:  IM    
Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7 E4, 9220, Aalborg, Denmark.
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MeSH Terms
Anaerobic Threshold / physiology*
Energy Metabolism / physiology*
Extracellular Fluid / chemistry,  physiology
Hydrogen-Ion Concentration
Intracellular Fluid / chemistry,  physiology
Muscle, Skeletal / chemistry*,  physiology*
Physical Exertion / physiology*
Young Adult
Reg. No./Substance:

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