Zone 2 Power vs Heart Rate

Regarding zones, there are several common zone systems. And they all give different results. For example a 2 hour zone2 ride two days ago:

Top is Coggan HR zones, bottom is Friel HR zones. Both use LTHR. Both give very different views. When I ride zone2, I train to power and ignore heart rate (note: except for special circumstances). Have been happy with the results of using power only for zone2 training.

And Friel mapping from 1-5c to names:

And here is Garmin Connect view using my custom zone settings based on LTHR:

I happened to start 5 years ago with using the Friel HR zones. They map fairly well with my power zones. So I am happy using Friel HR zones.

Here is a long list of HR zones models:

Personally I believe HR zones based on LTHR work well and recommend them, however there isn’t one right answer.