Ventilatory, lactate-derived and catecholamine thresholds during incremental treadmill running: relationship and...

Area of Science:

• Exercise Physiology
• Sports Science
• Biochemistry

Background:

• Anaerobic threshold is a key metric for exercise training recommendations.
• Various physiological parameters can estimate anaerobic threshold.
• Understanding the reproducibility and relationship between different threshold measures is crucial for accurate training prescription.

Purpose of the Study:

• To investigate the relationship between ventilatory, lactate-derived, and catecholamine thresholds during incremental treadmill exercise.
• To assess the reproducibility of these different threshold measurements.
• To inform training recommendations by comparing the reliability of various physiological markers.

Main Methods:

• Eleven male subjects performed two incremental treadmill tests within a week.
• Lactate threshold (LT) and individual anaerobic threshold (IAT) were determined from blood lactate levels.
• Ventilatory thresholds were identified using the V-slope method (AT) and end-tidal CO2 (RCP). Catecholamine thresholds (epinephrine and norepinephrine) were also measured.

Main Results:

• Ventilatory (AT, RCP) and lactate-derived thresholds (LT, IAT) demonstrated high test-retest reproducibility (r=0.88-0.97).
• Catecholamine thresholds (epinephrine, norepinephrine) showed poor reproducibility (r=0.46-0.49) and occurred significantly below LT and AT.
• Lactate-derived and ventilatory thresholds were closely correlated (r=0.70-0.95), despite systematic differences (LT ~4% below AT; IAT ~7-8% above RCP).

Conclusions:

• Ventilatory and lactate-derived thresholds offer reliable and reproducible measures for exercise training recommendations.
• Catecholamine thresholds are not sufficiently reproducible for practical application in training prescription.
• Systematic differences between lactate and ventilatory thresholds necessitate careful consideration when formulating training guidelines.