Do these AeT test results make sense? And how much can AnT change over time?

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  • #36354


    After a few months of easy volume to improve my aerobic capacity, this week I’m starting Mike Foote’s Big Vert plan. Yesterday I performed the heart rate drift test outdoors to estimate my AeT. It seems to have gone well—here are my results (a screenshot from TrainingPeaks is also attached):

    Initial HR: 144
    Average HR: 144
    Pa:Hr: 4.94%

    Based on those results, I have a couple of questions:

    1. Am I correct to think that my AeT is (roughly) 144, and I should set that as the top of my Z2? The instructions say “If the Pa:Hr is greater than 5% your initial HR/pace was above your Aerobic Threshold and you should do the test again at a lower HR,” but I’m not totally clear on whether 5% is actually the “magic number” we should be aiming for, or just a maximum value.

    2. I’m scheduled to perform the lactate threshold test in 2 days, but am considering skipping it. I’m fairly confident I have ADS, and so I’m not sure a max effort workout would be helpful right now. When I’ve tested my AnT in the past, it’s been around 175. However, the last check was 6 months ago, and during a race. I haven’t done any intense training since then, so could my AnT have changed significantly?

    So, given those estimates, does it make sense to assume I have ADS and skip the AnT test until my AeT improves?


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    Reed on #36375

    Hi Zac,

    The amount of decoupling (pace : heart rate) is pretty low, and the slight elevation could even account for a bit of that, I think. So, yes, given that you were able to sustain that pace for an hour, it seems that your aerobic threshold (AeT) heart rate is probably not lower than ~145bpm. It might be higher, but there’s no downside to being conservative and targeting a lower heart rate.

    It looks like you ran this at a 9:30 min/mi pace. You might see some improvement and grab low-hanging fruit by running 20 miles per week at 10min/mi or <145bpm for a few months. A hard run (anaerobic threshold field test) won’t hurt and might give you useful information; it also won’t be as helpful as more time at lower intensities.


    Zac on #36417

    Thanks, Reed! I really appreciate the feedback—that helps confirm what I (mostly) suspected. I’m going to take your advice and be conservative with my pace for a few months. The plan calls for a ton of easy running for the first 9 weeks anyway, so it shouldn’t be a huge adjustment. Looking forward to it and optimistic that I’ll see some improvement!

    Anonymous on #36456

    What Reed said! You had almost no drift (144 / 143), so AeT is probably higher than 145. As Reed said, you could do another test (at 150 or 155) or just train at 145 to be conservative.

    If you’ve tested your AnT recently, then you probably don’t need to again. The area to focus on is AeT for now.

    Zac on #36700

    @sws Thanks, Scott! I’ll do another AeT test in a few weeks, but for now continue to train at <145. I really appreciate the feedback, this forum is an amazing resource.

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