Journal of Applied Physiology Track the topics, authors and articles important to you
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 97: 1077-1081, 2004. First published May 7, 2004; doi:10.1152/japplphysiol.01321.2003
8750-7587/04 $5.00
This Article
Right arrow Full Text Free
Right arrow Full Text (PDF) Free
Right arrow All Versions of this Article:
97/3/1077    most recent
01321.2003v1
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (12)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Haseler, L. J.
Right arrow Articles by Richardson, R. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Haseler, L. J.
Right arrow Articles by Richardson, R. S.

Skeletal muscle oxidative metabolism in sedentary humans: 31P-MRS assessment of O2 supply and demand limitations

Luke J. Haseler,1 Alexander P. Lin,2 and Russell S. Richardson1

1Department of Medicine, University of California, San Diego, La Jolla 92093-0623; and 2Huntington Medical Research Institutes, Pasadena, California 91105

Submitted 10 December 2003 ; accepted in final form 4 May 2004

Previously, it was demonstrated in exercise-trained humans that phosphocreatine (PCr) recovery is significantly altered by fraction of inspired O2 (FIO2), suggesting that in this population under normoxic conditions, O2 availability limits maximal oxidative rate. Haseler LJ, Hogan ML, and Richardson RS. J Appl Physiol 86: 2013–2018, 1999. To further elucidate these population-specific limitations to metabolic rate, we used 31P-magnetic resonance spectroscopy to study the exercising human gastrocnemius muscle under conditions of varied FIO2 in sedentary subjects. To test the hypothesis that PCr recovery from submaximal exercise in sedentary subjects is not limited by O2 availability, but rather by their mitochondrial capacity, six sedentary subjects performed three bouts of 6-min steady-state submaximal plantar flexion exercise followed by 5 min of recovery while breathing three different FIO2 (0.10, 0.21, and 1.00). PCr recovery time constants were significantly longer in hypoxia (47.0 ± 3.2 s), but there was no difference between hyperoxia (31.8 ± 1.9 s) and normoxia (30.0 ± 2.1 s) (mean ± SE). End-exercise pH was not significantly different across treatments. These results suggest that the maximal muscle oxidative rate of these sedentary subjects, unlike their exercise-trained counterparts, is limited by mitochondrial capacity and not O2 availability in normoxia. Additionally, the significant elongation of PCr recovery in these subjects in hypoxia illustrates the reliance on O2 supply at the other end of the O2 availability spectrum in both sedentary and active populations.

oxidative capacity; mitochondria; exercise; intracellular oxygenation; 31-phosphorous-magnetic resonance spectroscopy


Address for reprint requests and other correspondence: L. J. Haseler, Gold Coast Campus Griffith University, PMB 50 Gold Coast Mail Centre, Queensland 9726, Australia (E-mail: L.Haseler{at}griffith.edu.au).




This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
L. J. Haseler, A. Lin, J. Hoff, and R. S. Richardson
Oxygen availability and PCr recovery rate in untrained human calf muscle: evidence of metabolic limitation in normoxia
Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2007; 293(5): R2046 - R2051.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
P. E. di Prampero, C. Capelli, G. Ferretti, A. W. Sheel, Y. O. Schumacher, K. Roecker, H. Bay Nielsen, U. Hoffmann, E. Gams, J. D Schipke, et al.
Comment on Point:Counterpoint "In health and in a normoxic environment, VO2 max is/is not limited primarily by cardiac output and locomotor muscle blood flow"
J Appl Physiol, March 1, 2006; 100(3): 1086 - 1086.
[Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
J. A. L. Calbet, H.-C. Holmberg, H. Rosdahl, G. van Hall, M. Jensen-Urstad, and B. Saltin
Why do arms extract less oxygen than legs during exercise?
Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2005; 289(5): R1448 - R1458.
[Abstract] [Full Text] [PDF]

Home page
 Exp PhysiolHome page
L. F Ferreira, A. J Harper, D. K Townsend, B. J Lutjemeier, and T. J Barstow
Kinetics of estimated human muscle capillary blood flow during recovery from exercise
Exp Physiol, September 1, 2005; 90(5): 715 - 726.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
K. R. Short, M. L. Bigelow, J. Kahl, R. Singh, J. Coenen-Schimke, S. Raghavakaimal, and K. S. Nair
From the Cover: Decline in skeletal muscle mitochondrial function with aging in humans
PNAS, April 12, 2005; 102(15): 5618 - 5623.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2004 by the American Physiological Society.