Limitations to V̇O2max in humans after blood retransfusion

D. L. Turner, H. Hoppeler, C. Noti, H. P. Gurtner, H. Gerber, F. Schena, B. Kayser, G. Ferretti

Research output: Contribution to journalArticlepeer-review

Abstract

Seven young, healthy male subjects performed maximal exercise on a cycloergometer with central venous and arterial catheters, before and after autologous retransfusion of red blood cells. Maximal oxygen consumption (V̇O2max), blood gas composition and haemodynamic variables were measured, in order to test the hypothesis of monofactorial vs polyfactorial V̇O2max limitation. Autologous blood retransfusion led to significant increases in haemoglobin concentration and consequently arterial oxygen concentration during maximal exercise, while maximal cardiac output, heart rate and stroke volume were not significantly changed. The relationship between maximal oxygen delivery (cardiac output·arterial oxygen concentration; (Q̇·CaO2 )max and maximal oxygen consumption in this study was V̇O2max (L·min-1) = 0.02 +0.64·(Q̇·CaO2 )max (L·min-1), the slope being significantly less than unity. These results suggest that (Q̇·CaO2 )max plays but a fractional role in limiting V̇O2max, in agreement with recent models concerning the resistance to oxygen flow in the respiratory system (di Prampero and Ferretti, Respir. Physiol. 80: 113-128, 1990). The relative increase in V̇O2max after blood retransfusion matched the relative increase in 'aerobic performance', measured as the maximal power output that could be maintained aerobically for 30 min. Furthermore, the increase in maximal power output (15 ± 3 watts) could account for almost all of the extra oxygen consumption. This match suggests that there is an inability to fully utilize muscle oxidative capacity in the normocythaemic state.

Original languageEnglish
Pages (from-to)329-341
Number of pages13
JournalRespiration Physiology
Volume92
Issue number3
DOIs
Publication statusPublished - 1993

Keywords

  • blood retransfusion
  • Blood retransfusion, maximal exercise
  • Cardiac output, blood retransfusion
  • Exercise, maximal
  • Mammals, humans
  • Oxygen delivery, maximal exercise

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine

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