Estimating aerobic threshold using @marco_alt HRV Logger has been briefly discussed on the Iñigo San Millán training model thread. It is somewhat relevant there as ISM’s “Zone 2” seems to fall right at LT1. However, a deeper dive into this subject seems to belong here.
After some initial confusion on my part, I managed to conduct a little ramp test today to see where .75 DFA/alpha 1 fell. I based the protocol on @BJRMD blog, etc, 6 min steps where you throw out the first reading at 2 mins, achieve a sort of steady state, and take readings at 4min and 6min (again, each stage is 6min total).
The second two data points during each stage were close to each other so I feel confident in my execution of protocol.
HR @ LT1 - 129-131bpm (measured several times over the last 18 months)
HR @ 0.7-0.8 DFA (alpha 1) - 128-130bpm
I did a final 6 min stage at 134/135bpm and DFA/alpha1 was well below .75 for all three data points of the stage.
(used a Wahoo Tickr via Bluetooth, thanks for the tip @carytb )