Effects of training and immobilization on V̇O2 and DO2 in dog gastrocnemius muscle in situ

D. E. Bebout, M. C. Hogan, S. C. Hempleman, P. D. Wagner

Research output: Contribution to journalArticle

52 Scopus citations

Abstract

To investigate the effects of exercise training and immobilization on peak O2 uptake (V̇O2) and effective O2 diffusive conductance (DO2) in skeletal muscle, three groups of purpose-bred hounds [control (C), exercise trained (E), and immobilized (I)] were studied. Group E exercised on a treadmill 1 h/day, 5 days/wk for 8 wk, while groups C and I were cage confined for 8 wk, with group I undergoing left hindlimb immobilization for the last 3 wk. Thereafter, each dog's left gastrocnemius was surgically isolated, pump perfused, and electrically stimulated to elicit peak V̇O2 in situ at three levels of arterial oxygenation. O2 delivery [(arterial O2 concentration x muscle blood flow)/100 g muscle] was kept constant among the three groups at each level of arterial oxygenation. Compared with group C, peak V̇O2/100 g muscle was 38, 33, and 19% greater and DO2/100 g muscle was 71, 75, and 68% greater during normoxia, moderate hypoxia, and severe hypoxia, respectively, in group E (P < 0.02), whereas no differences from control were found in group I. We conclude that O2 delivery is not the unique determinant of peak V̇O2 and that exercise training improves the functional blood-tissue gas exchange properties of the muscle itself. Immobilization sufficient to reduce muscle weight by 31% and citrate synthase activity by 68% has no effect on peak V̇O2/100 g muscle or DO2/100 g muscle.

Original languageEnglish (US)
Pages (from-to)1697-1703
Number of pages7
JournalJournal of Applied Physiology
Volume74
Issue number4
StatePublished - Jan 1 1993
Externally publishedYes

Keywords

  • endurance training
  • hypoxia
  • muscle atrophy
  • muscle diffusing capacity
  • oxygen diffusing capacity
  • oxygen diffusion
  • oxygen extraction

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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