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Induced hypervolemia, cardiac function, VO2max, and performance of elite cyclists
D E Warburton1, N Gledhill, V K Jamnik
1Kinesiology and Health Science, York University, North York, Ontario, Canada.
Medicine and Science in Sports and Exercise
|June 23, 1999
Summary
Plasma volume expansion does not enhance VO2max or endurance performance in elite endurance-trained cyclists. Elite athletes may already have optimal blood volume, potentially limited by diastolic reserve capacity.
Area of Science:
- Exercise Physiology
- Sports Science
- Cardiovascular Physiology
Background:
- Elite endurance-trained (ET) cyclists possess high blood volume (BV) and VO2max.
- Plasma volume expansion (PVexp) is a potential ergogenic aid.
Purpose of the Study:
- To investigate if PVexp further enhances cardiac function, VO2max, and endurance performance in elite ET cyclists.
- To determine if elite ET athletes benefit from additional BV expansion.
Main Methods:
- Double-blind, cross-over study with nine male ET cyclists.
- Measurements taken before and after sham PVexp, PVexp (6% dextran), and normocythemia.
- Assessed cardiac output, stroke volume, VO2max, and time to exhaustion.
Main Results:
- PVexp increased BV by 547 mL.
- Maximal cardiac output and stroke volume increased post-PVexp.
- These increases only compensated for hemodilution; VO2max and endurance performance remained unchanged.
Conclusions:
- BV expansion does not improve VO2max or endurance performance in elite ET cyclists.
- Elite ET athletes may have reached their optimal BV, potentially limited by diastolic reserve.
- Further BV expansion offers no performance benefits for this population.