Isolated quadriceps training increases maximal exercise capacity in chronic heart failure: The role of skeletal muscle convective and diffusive oxygen transport

Fabio Esposito, Van Reese, Ralph Shabetai, Peter D. Wagner, Russell S. Richardson

Research output: Contribution to journalArticlepeer-review

Abstract

Objectives: This study sought to elucidate the mechanisms responsible for the benefits of small muscle mass exercise training in patients with chronic heart failure (CHF). Background: How central cardiorespiratory and/or peripheral skeletal muscle factors are altered with small muscle mass training in CHF is unknown. Methods: We studied muscle structure, and oxygen (O2) transport and metabolism at maximal cycle (whole-body) and knee-extensor exercise (KE) (small muscle mass) in 6 healthy controls and 6 patients with CHF who then performed 8 weeks of KE training (both legs, separately) and repeated these assessments. Results: Pre-training cycling and KE peak leg O2 uptake (Vo2peak) were ∼17% and ∼15% lower, respectively, in the patients compared with controls. Structurally, KE training increased quadriceps muscle capillarity and mitochondrial density by ∼21% and ∼25%, respectively. Functionally, despite not altering maximal cardiac output, KE training increased maximal O2 delivery (∼54%), arterial-venous O2 difference (∼10%), and muscle O2 diffusive conductance (DMO2) (∼39%) (assessed during KE), thereby increasing single-leg Vo2peak by ∼53%, to a level exceeding that of the untrained controls. Post-training, during maximal cycling, O2 delivery (∼40%), arterial-venous O2 difference (∼15%), and DMO2 (∼52%) all increased, yielding an increase in Vo2peak of ∼40%, matching the controls. Conclusions: In the face of continued central limitations, clear improvements in muscle structure, peripheral convective and diffusive O2 transport, and subsequently, O2 utilization support the efficacy of local skeletal muscle training as a powerful approach to combat exercise intolerance in CHF.

Original languageEnglish
Pages (from-to)1353-1362
Number of pages10
JournalJournal of the American College of Cardiology
Volume58
Issue number13
DOIs
Publication statusPublished - Sep 20 2011

Keywords

  • blood flow
  • cardiac output
  • hyperoxia
  • oxygen supply
  • oxygen utilization
  • skeletal muscle

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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