Thank you for reaching out to the community!

Max Heart Strain represents the peak value of Heart Strain recorded during each workout. Heart Strain is a measurement based on the ST-segment deviation recorded by the Frontier X from the CC5 Lead position. This deviation could be influenced by factors such as oxygen deprivation to a part of your heart, electrolyte imbalance, and conduction defects.

The key difference is:

Heart Strain is a continuous measurement throughout the workout, showing variations in real time.
Max Heart Strain is the highest recorded value of Heart Strain during the session.
Since Heart Strain fluctuates during exercise, the max value may differ significantly from the average or typical strain level seen throughout the workout.

Hope this helps! Let us know on support@fourthfrontier.com you have further questions.