XSS in a Nordic Cross Country session

I am new in Xert. I like this Software, but i am not sure, if it is suitable for me. Sorry for my bad english. I hope, that i can explain the situation correctly. So we live in Germany and in Winter, we do a lot of nordic cross country (skating), because of weather conditions its outside difficult to cycle, but the main sport is cycling. So i have while skiing only heartrate, speed and distance and altitude. Yesterday i got for 10km and a average heartrate of 174 bpm only a xss score 9. TP shows me a 112 Hrtss and Strava which has no TSS, but something different shows me 116.
I think xss is to low. What can i do or how to deal with it to use in future Xert as an appropriate tool.

Thank you very much



What device were you using to record the workout?

I am curious to get input on this as well. Using my Garmin (with HR strap) I got an XSS of 159 on my last nordic session (2hr50min, AvgHR=133, 32.5K), but when I use my Apple Watch (with optical HR sensor) I get a much lower XSS.

I use Polar Vantage V and i send the data to TP and Strava.

It might not be a 100% reply. But after using Xert for both cycling and running (with Stryd/power), I have a look on my XC classic sessions average HR and usually calculate around 1-1,5 points of XSS per minute of exercise. If it felt really easy maybe around 0,7-1 XSS/minute.