Training effect near zero for a 60 min run with HR at zones 4 and 5 for 55 minutes

I’m using a Fenix 6S pro Solar. My Max HR is 169. I’m female 64.

I use a Fenix 6S Pro Solar to record indoor runs and biking. Usually the training effect is accurate. However, in the last week I have had weirdly low training effects.

I ran 60 minutes (endurance run) where my HR was mainly in Zone 4 (56%) with 37% at the low end of the Zone 5. I got a training effect of 0.2 Aerobic (0 Anaerobic) and a Training load of 2.

Usually I get reasonable Training loads and effects. Can anyone explain what happened?



  • First of all I'd double check the Max HR setting on watch, in User Profile (not the one in the Activity!). If you have the auto-detection on, it might got set to a new excessively high number (due to a HR sensor error). And check also the LTHR and Resting HR, to see whether they are set to reasonable values, too.

    Another possible reason might be accidentally wrong weight or height. Unfortunately the system allows errors by orders of magnitude, so for example if you confuse a decimal comma with a dot, it may result in a weight of high hundreds of kilograms. And such huge value would have impact on a lot of fitness metrics as well.

  • Rebooting the watch to factory settings are reloading fixed it!

  • Not reloading the run, that is permanently not right. Reloading the backup. I think it was a sw bug, Tested with a 20 minute run today. HR in zone 4 for most, similar pace. 2.9 aerobic, training load 55.