This article explains which lactate models are available in iQO2 to determine the anaerobic threshold (ANT). ANT is defined as the workload causing a rapid rise in blood lactate indicating the upper limit of equilibrium between lactate production and clearance.

Available methods to determine AT based on changes in blood lactate response to progressive exercise.

  1. Fixed lactate value
    • Default set to 4 mmol/L.
    • Customizable range: 2.8 mmol/L – 5.2 mmol/L.
    • History: Mader 1976 ANT = 4mmol / SJODIN & JACOBS 1981 ANT = OBLA = 4mmol / HECK & MADER 1985 ANT = 4mmol/L / BORCH 1993 ANT = 3mmol.

  2. D-max
    • ANT is defined as the point on curve at maximal distance from line connecting starting and finishing workloads.
    • History: Cheng 1992.

  3. Modified D-Max
    • Same method as D-max but Modified Dmax utilising the aerobic threshold instead of first workload as start point.
    • ANT is defined as the point of the curve at maximal distance from line connecting aerobic threshold and finishing workloads.
    • History: ADAPT 1995.

  4. Stegmann
    • Based on a model to define workload at maximal lactate steady state – rate of diffusion in equilibrium with rate of elimination.
    • ANT is defined as the equilibrium between diffusion vs. the rate of elimination.
    • History: Stegmann 1981.

  5. Tangent
    • ANT is defined as a fixed slope point on lactate power curve whose tangent is equal to 51°.
    • Default set to 51°.
    • Customizable range: free choice.
    • History: Keul 1979 ANT = 51°.

  6. Aerobic threshold + 1.5 mmol
    • ANT is defined as the aerobic threshold + 1.5 mmol/l.
    • History: COYLE 1984 ANT = non-linear increase of > 1mmol.


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