Muscle blood flow and distribution determine maximal VO2 of contracting muscle

Wendell N. Stainsby, William F. Brechue, Bill T. Ameredes

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

During repetitive contractions, the VO2 of the dog gastrocnemius-plantaris muscle rose with the contraction frequency up to a maximal value and then decreased as contraction frequency was increased further. PVO2 was constant over most of the contraction frequency range. Reducing perfusion pressure/blood flow reduced VO2max with a constant PVO2. During these maneuvers the diffusion conductance, DCO2 (VO2/PVO2), changed with VO2. Raising the perfusion pressure/flow with a pump increased VO2 with a small rise in PVO2 so that DCO2 also increased. Removing tension from the muscle between contractions elevated VO2 and DCO2 without a change in perfusion pressure. Hypoxemia decreased VO2 with a decrease in PVO2; DCO2 remained constant. A three-compartment mathematical model, based on microsphere measurements of regional flow, was used to illustrate how regional flow variations may exist, and how they are poorly revealed in the mixed whole-muscle venous blood. The model shows VO2·g−1 strongly related to flow. As VO2·g−1 increased as Q·g−1 increased, extraction decreased, and DCO2 increased.

Original languageEnglish (US)
Pages (from-to)43-46
Number of pages4
JournalMedicine and Science in Sports and Exercise
Volume27
Issue number1
DOIs
StatePublished - Jan 1995
Externally publishedYes

Keywords

  • Hypoxemia
  • Ischemia
  • Normoxia
  • O diffusion
  • Vascular compression

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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