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Plasma lactate and ventilation thresholds in trained and untrained cyclists
Journal of Applied Physiology (Bethesda, Md. : 1985)
|March 1, 1986
Summary
Trained cyclists show similar plasma lactate threshold (PLT) and ventilation threshold (VT) at higher intensities. Untrained individuals exhibit a higher PLT than VT, suggesting differences in lactate processing between fitness levels.
Area of Science:
- Exercise Physiology
- Sports Science
- Human Performance
Background:
- The plasma lactate threshold (PLT) and ventilation threshold (VT) are key indicators of endurance fitness.
- Understanding the relationship between PLT and VT in trained versus untrained individuals is crucial for exercise prescription.
Purpose of the Study:
- To investigate whether the plasma lactate threshold (PLT) and ventilation threshold (VT) occur at the same work rate in trained cyclists and untrained sedentary men.
- To explore potential differences in lactate kinetics and their relationship with ventilatory measures between different fitness levels.
Main Methods:
- Incremental leg-cycling tests were performed until volitional exhaustion.
- Plasma lactate concentration ([La]) and expired minute ventilation (VE) were measured to determine PLT and VT.
- VO2 max was assessed as a measure of maximal aerobic capacity.
Main Results:
- Trained cyclists had significantly higher VO2 max and VT compared to untrained individuals.
- In trained cyclists, PLT and VT occurred at similar percentages of VO2 max.
- Untrained individuals showed a significantly higher PLT than VT, indicating a different physiological response.
Conclusions:
- The relationship between PLT and VT differs between trained and untrained populations.
- Variations in lactate diffusion and/or removal processes may explain the observed differences in PLT and VT relationships.
- These findings highlight the importance of considering individual fitness levels when interpreting exercise performance markers.