Pacing endurance rides by power or HR? Benefits of short endurance rides

[WildWill]

I do most of my endurance rides by power, but I record my HR to allow me to assess my HR Decoupling.

Check out this thread

Can I test my aerobic base?

Was reading up on it and I’m curious if I could test my aerobic base just to know where it is at, just curious, for example doing a 3 hour endurance spin of 65% to 75% of my FTP using my HR as a guide.