Brian, My guess is that you have a combination of things going on here. Firstly I would focus on the AeT and make sure you’re training smartly there which sounds like you are. The drift tests when performed correctly don’t really lie. If you for instance start a drift test at 140bpm and drift more than 5% then there’s a reason you can’t sustain that effort level without drift even though it feels quite “easy”. Stick with it and it will improve. For the AnT I will commonly use a 60 min effort (not counting warmup and cool down) as my metric in fairly well trained athletes. I like the 30 -45 min version of the test for folks that maybe arent quite as well trained as I find that gives a more accurate picture of what they’re capable of. If you’re not well trained for that kind of effort you may tend to blowup before 60 minutes more from a muscular endurance/neuro limitation than a metabolic one if that makes sense. You may want to repeat the test for AnT with the 60 min duration and see if that yields different results. The good news is you may well have a fairly efficient carb burning motor and ability to produce power, now we just need to chip away at the lower intensity efficiency. As for resting HR I haven’t ever found much correlation to it and the above discussion. I have seen athletes with a fairly low and fairly high resting HR and similar threshold numbers (and vice versa) Relative effort sadly isn’t a great gauge of most of these things which is why we need accurate zones and HR monitor. I can run at about 10 bpm above my AeT all the while swearing this must be a super useful low intensity effort but of course when I look at the data from that effort level I’m drifting like crazy.

This is n=1 but I’ve found that my resting HR varies depending on the watch. I upgraded from a Garmin Instinct to a Fenix 6 over the summer and I added ~10 bpm to my RHR (~42-45 to ~52-55). So, who knows? Glad to hear there isn’t any correlation.