Best tests for AeT, or, why isn't HR drift covered in the new book

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  • #18431

    I’ve seen a lot of discussion on this site about HR drift as a method for determining AeT, but in the new book (which by the way, is amazing), the only tests mentioned are MAF method, nose-breathing (ventilatory marker test), lactate step test, and the gas exchange test.

    My questions are: why isn’t HR drift in the book? Is it because it is less reliable than the other 4 methods? Obviously gas exchange is the most accurate, but what is the ranking for all five tests in terms of accuracy (including HR drift)?

    Thanks so much for the hard work the Uphill Athlete team has done to help us all take concrete steps towards greater fitness in the mountains!

  • Inactive
    Anonymous on #18468


    We decided not to include the HR drift test in the new book because it requires one to have a Training Peaks account. While we are big believers in the value of TP we are not affiliated with them in anyway and in fact pay them quite a lot of money each month for the use of their platform (which shows how valuable we think it is). To make Training Peaks a requirement for the use of any part of the book seemed too much of a commercial endorsement to all three of Kilian, Steve and me. We were afraid there might be backlash and we wanted anyone to be able to use this book to create a plan for themselves. So we left what could be construed as a commercial endorsement of TP out.

    We use this HR drift (HR decoupling as TP terms it) with all of our coached clients. We have seen very strong correlation with gas AeT tests (probably approaching 95%). So, I would rank it second or 3rd behind the Gas test and a lactate test. Definitely more accurate for more people than the others. MAF works great for most people but I have seen it be way off in both directions on several occasions. Same for the nose breathing test. For those with a good aerobic training history I’d say it is corresponds perfectly with a lactate test. But when if one does not have that aerobic background I have seen it off by a mile.

    Not everything made it onto the first or the second book which is why we provide so much free information on this site.

    I hope this helps.


    patrick.nygren on #18542

    Hi Scott, thanks for your response, totally makes sense! And thank you for making your knowledge available independent of commercial endorsements. Really helpful to get your take on the accuracy of various AeT tests.


    Participant on #18858

    We decided not to include the HR drift test in the new book because it requires one to have a Training Peaks account.

    I am puzzled by this statement. I don’t see any need for Training Peaks.

    Anyone can do a training session at constant intensity and calculate their heart rate drift during the session. No need for Training Peaks for that.

    If the intensity is varied during the session, it becomes a bit more difficult, but in that particular situation, the Training Peaks method is rubbish anyway. As far as I know, they use Joe Friel’s method, which is based on an assumption that heart rate is proportional to training intensity. That is of course not the case, since our heart rate isn’t 0 at 0 training intensity. In that situation, I prefer to use my own correction for intensity. So again no need for Training Peaks.

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