Welcome to the LT-web services!

This site contains online tools for analyzing lactate and heart rate curves and to estimate various aerobic and anaerobic lactate thresholds and markers.


We offer online services for the analysis of blood lactate and heart rate measurements performed during incremental (e.g. treadmill) tests. Functionalities include lactate and heart rate model fitting and evaluation, aerobic lactate threshold and anaerobic lactate threshold (also sometimes referred as maximal lactate steady state - MLSS, or lactate turnpoint) estimations. Currently, the following models are available for lactate model fitting:

  • Exponential
  • 3rd and 4th degree polynomial
  • Cubic and smooth spline
A robust version of the 3rd and 4th degree polynomial is also available, which is less sensitive to outliers.

Currently the following models are available for heart rate model fitting:

  • Linear
  • Piecewise linear
  • Smooth spline

We also show some examples in various programming languages to help you with the integration of our services in 3rd party software. Demos using our services are available to download for Microsoft Excel, and LibreOffice Calc. Google Sheets demo is available upon request. Standalone web-based demo is available for lactate analysis.

Terms and conditions

For personal use these services are free of charge. A commercial license is available upon request. Please note that registration is mandatory for using our services. Also note that by registering or using the services you accept our Terms of Service.


Name: Ákos Utasi
Email: autasi@gmail.com