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Attenuated relationship between cardiac output and oxygen uptake during high-intensity exercise
J D Trinity1, J F Lee, M D Pahnke
1Human Performance Laboratory, Department of Kinesiology and Health Education, The University of Texas at Austin, USA. joel.trinity@utah.edu
Acta Physiologica (Oxford, England)
|July 28, 2011
Summary
The relationship between cardiac output (CO) and oxygen consumption (VO2) is not linear during intense cycling exercise. Cardiovascular function shows signs of compromise before reaching maximal oxygen uptake (VO2max).
Area of Science:
- Exercise Physiology
- Cardiovascular Physiology
- Sports Science
Background:
- The relationship between cardiac output (CO) and oxygen consumption (VO2) has traditionally been viewed as linear.
- Recent research suggests this relationship may not hold true across all exercise intensities.
Purpose of the Study:
- To investigate the relationship between cardiac output (CO), stroke volume (SV), and oxygen consumption (VO2) during cycling exercise.
- To determine CO and SV responses across a range of exercise intensities from 40% to 100% of VO2max.
Main Methods:
- Ten well-trained cyclists completed discontinuous exercise bouts.
- Measurements included cardiac output (CO), stroke volume (SV), and oxygen consumption (VO2).
Main Results:
- The rate of increase in CO relative to VO2 decreased significantly at higher exercise intensities (70-100% VO2max).
- Stroke volume (SV) was reduced at maximal exercise intensities compared to submaximal intensities.
- Arteriovenous oxygen difference increased with exercise intensity.
Conclusions:
- Cardiovascular function shows signs of compromise before reaching maximal oxygen uptake (VO2max).
- The non-linear relationship between CO and VO2 highlights limitations in cardiovascular adaptation at high exercise loads.
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