A new method for detecting anaerobic threshold by gas exchange

Area of Science:

• Exercise Physiology
• Respiratory Physiology
• Biochemistry

Background:

• Lactate accumulation during exercise leads to excess carbon dioxide (CO2) production due to buffering by bicarbonate (HCO3-).
• Identifying the anaerobic threshold (AT) is crucial for understanding exercise physiology and performance.

Purpose of the Study:

• To develop and validate a computerized method, the V-slope method, for detecting the anaerobic threshold (AT).
• To compare the V-slope method's accuracy and reliability against traditional methods and other physiological markers.

Main Methods:

• Utilized computerized regression analysis of CO2 uptake (VCO2) versus O2 uptake (VO2) plots to identify excess CO2 output.
• Conducted incremental exercise tests on 10 subjects.
• Analyzed minute ventilation versus VCO2 plots to identify the respiratory compensation point.

Main Results:

• The V-slope method accurately detected the AT, which closely predicted lactate and bicarbonate thresholds.
• The gas exchange AT corresponded to a slight increase in lactate above the defined lactate threshold.
• The V-slope method provided a more reliable determination of AT compared to visual methods, with no significant difference in VO2 at AT.
• The respiratory compensation point was consistently found at a higher VO2 than the AT.

Conclusions:

• The V-slope method offers a reliable and advantageous approach for determining the anaerobic threshold.
• This method is superior to techniques relying on breathing patterns or chemosensitivity.
• The V-slope method provides a precise physiological marker for exercise intensity assessment.