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Heart rate deflection point as a strategy to defend stroke volume during incremental exercise
Pierre-Marie Lepretre1, Carl Foster, Jean-Pierre Koralsztein
1LEPHE, Department of STAPS, University of Evry Val d'Essonne, Sport Medicine Center of the CCAS, 2 Ave. Richerand, Paris F-75010, France. lepretre.pierre-marie@wanadoo.fr
Journal of Applied Physiology (Bethesda, Md. : 1985)
|December 25, 2004
Summary
The heart rate deflection point (HRDP) in cyclists often coincides with peak stroke volume (SVmax), indicating optimal cardiac function during intense exercise. This finding suggests HRDP can predict maximal stroke volume achievement in trained athletes.
Area of Science:
- Exercise Physiology
- Cardiovascular Physiology
- Sports Science
Background:
- The heart rate deflection point (HRDP) is an indicator of exercise intensity.
- Maximal stroke volume (SVmax) is crucial for endurance performance.
- The relationship between HRDP and SVmax achievement in trained athletes requires further investigation.
Purpose of the Study:
- To determine if the HRDP in the heart rate-power relationship aligns with SVmax attainment in endurance-trained cyclists.
- To investigate the predictive value of HRDP for SVmax in this population.
Main Methods:
- Twenty-two male cyclists performed graded cycling exercise.
- Thoracic impedance continuously measured heart rate (HR) and stroke volume (SV).
- HRDP was identified using third-order curvilinear regression.
Main Results:
- A HRDP occurred in 72.7% of subjects at approximately 90% of maximal HR.
- In the HRDP group, SV increased until 78% of power at VO2max, while in the no-HRDP group, it increased until 94%.
- SV decreased before exhaustion in the HRDP group, and HRDP power output predicted 62% of SVmax variance.
Conclusions:
- In well-trained cyclists, the HRDP often coincides with SVmax attainment.
- HRDP can serve as a non-invasive marker for optimal cardiac work and SVmax during exercise.
- This relationship highlights the utility of HRDP in assessing cardiovascular adaptation to training.