The program calculates the maximum heart rate with the following formula: 210 – (0.65 x age) = maxHR. If the analysis founds a higher value from the measurement period than what the formula provides, the program notifies that the new found maximum heart rate is updated to the background information. If the program suggests, for example, a max heart rate of 220, it is a good idea to visually inspect the data and make sure that the value was found from a reliable data segment (and not e.g. from an error peak).
If you already know the maximum heart rate, it can be added to the background information for improving the accuracy of the analysis. In this case the analysis will use the entered value.