Premium
Attenuated relationship between cardiac output and oxygen uptake during high‐intensity exercise
Author(s) -
Trinity J. D.,
Lee J. F.,
Pahnke M. D.,
Beck K. C.,
Coyle E. F.
Publication year - 2012
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2011.02341.x
Subject(s) - stroke volume , vo2 max , cardiac output , heart rate , cardiology , exercise intensity , medicine , intensity (physics) , exercise physiology , physical exercise , physical therapy , hemodynamics , blood pressure , physics , quantum mechanics
Aim: Recent findings have challenged the belief that the cardiac output (CO) and oxygen consumption ( V O 2 ) relationship is linear from rest to maximal exercise. The purpose of this study was to determine the CO and stroke volume (SV) response to a range of exercise intensities, 40–100% of V O 2max , during cycling.Methods: Ten well‐trained cyclists performed a series of discontinuous exercise bouts to determine the CO and SV vs. V O 2 responses.Results: The rate of increase in CO, relative to V O 2 , during exercise from 40 to 70% of V O 2max was 4.4 ± 1.4 L L −1 . During exercise at 70–100% of V O 2max , the rate of increase in CO was reduced to 2.1 ± 0.9 L L −1 ( P = 0.01). Stroke volume during exercise at 80–100% of V O 2max was reduced by 7% when compared to exercise at 50–70% of V O 2max (134 ± 5 vs. 143 ± 5 mL per beat, P = 0.02). Whole body arterial‐venous O 2 difference increased significantly as intensity increased.Conclusion: The observation that the rate of increase in CO is reduced as exercise intensity increases suggests that cardiovascular performance displays signs of compromised function before maximal V O 2 is reached.