Have been using the FR235 watch to train within heart rate zones for the last two months and have used the %MaxHR Data Field so far.
Have been reading about also using the %HRR to identify more accurate HR training zones.
I have configured the %HRR and Avg %HRR as Data Fields - but all it shows during activities is "--" !
Have I missed some configuration somewhere (watch, Connect) for setting the RestHR and MaxHR?