Great reply, and I think that your explanation makes perfectly sense. I did not processed the HRV data as to not add “noise” to the analysis: after all this is a discussion regarding alphaHRV.
I do believe that the theoretical grounds of the idea underlying estimation of thresholds is sound. The way I look at it is as a viable and non invasive way that resembles the determination of VT1/2 (done in lab via gas exchange). Under this perspective, what is really important is to have some reliable estimates of RespRate and alpha1 to determine the inflection points; their actual values should be irrelevant, but for software companies interested in business.