Hello Alex and TD team, just signed up for free version to test it.
One question: I’m very interested in doing Zone 2 training this winter, but HR based (bc of previous heart issues and the fact that I’m taking beta blockers it’s not totally safe for me to do an unsupervised FTP test.)
At one point you said your goal with HR mode was to have it adjust smart trainer resistance to keep the rider in the target HR zone. I assume that’s still in the works, or have you abandoned that idea?
Hi Peter and welcome. Really for Z2 HR training our free version is all you likely need. 
I have not completely abandoned it but questioned the value and exploring deeper discussions.
Most people doing hr training have simple intervals. Staying in zone is pretty easy once you determine the watts you need for that hr target. It might change next week but pressing + - should keep you at your target or using slope mode with a gear or cadence change.
That said what seems much simpler and just as useful is just how Garmin or polar do hr based running with beep sounds when you are out of zone if you want to veg out and watch Netflix for example. Does that make sense to you?
You can estimate your ftp from z2 hr and power if you know your max measured hr although maybe it’s different now. I would set zone 2 limit where you start to notice the slightest amount of breath change and reduce it by about 5 beats. Maffetone says 180-age-10 (due to drugs), his calc usually is pretty close. FTP does not matter that much but knowing your aerobic threshold AeT is for z2 training.
The Z2 work is really beneficial and hope you’re having a good experience / outcome to that.
I saw that TD has this feature where you can scale / put an offset of Power at specific HR (much like drawing a graph and connecting a best fit line). Does this serve the purpose you’re looking for?
The “Set Target HR and have trainer adjust automatically” is not a new thing, the complexity is actually greater cos every human is different and thus the HR response but it is definitely easier to control than having say - using cadence to control Power Targets.
You could use Garmin device to set the HR zones and have it “beep” when you’re out of the targeted zone (that’ what I do for my Z2 running and just slow down or walk when it beeps)
I think TD can also do the Target HR workout thing (if not you can create one for yourself within garmin’s ecosystem) and send it to Garmin.
Alternatively, you can also use the workout builder in intervals.icu (https://forum.intervals.icu/t/building-workout-using-zone-number-instead-of-percentage-range/)
It all depends on which ecosystem you’re most comfortable with. Having said that, I do understand that these are not what you’re looking for specifically. YOu want the trainer to be controlled by your HR.
Thanks. I already do use Garmin zones (with the beep) to set targets – but would rather have it in TD app to adjust resistance instead of just backing off (either cadence or downshift). As I mentioned, my ideal Z2 workout aligns HR between, say 60-70% (max is 166 on beta blockers based on my last cardiac stress test), while adjusting flywheel resistance. That will also work my muscles a bit more than just reducing cadence, I think. But I do understand the complexity given that even the best HR straps can glitch every now and then…I"ll look into intervals.icu too.
yeah… I’ve had quite a few HRMonitors, the latest is now Polar H10 which is good (dual BLE connections capability)
You’re basically looking for “HR Based Structured Workouts”. It’s great actually.