New z2 power and heartrate zones seem too low

[R2Tom]

So, some time ago, I made a post about the big differences in zone boundaries for athletes, which was shown in a paper:

Zone 2 Intensity: Comparison of Individual Variability Research

I came across research that uncovers just how challenging it is to define Zone 2 (Z2) boundaries and why fixed zones might not work for everyone. There are always questions about zones and their classification, so this study is worth a look. The study shows that physiological markers such as heart rate, lactate thresholds, and power output vary significantly between individuals—even among similarly trained athletes. This variability makes it almost impossible to create one-size-fits-all trainin…

So, yes, your boundaries can be completely different than the „default“ boundaries.

Some points which come to my mind reading your post:

1. Is it only one power meter, is it calibrated regularly?
2. heart rate drift test doesn‘t tell you where your boundaries are, it‘s more a test of durability I‘d say. And there are other factors which can influence the heart rate drift (heat, nutrition, hydration, …).
3. If you do a speech test, at the top of Z2 you still can talk one full sentence, wherein Z3 you can only talk in short phrases (as a rule of thumb). Did you do such a „test“?
4. There is a difference in cardiovascular endurance and muscle endurance, from your post I‘d say that you muscle is the „limiter“. What’s your weekly training hours for the last year? Is it consistent training? Did you consider adding strength training to strengthen your muscles?