HR Drift Test and Threshold Notification Discrepancy

  • Creator
  • #35510

    Hi everyone,
    On the 22nd of December I completed the heart rate drift test as I start another round of the Big Vert program.

    Everything went well and the first half gave me an average heart rate of 170bpm with the second half having an average of 177. Total percentage difference being approx 4.1%.

    I used this to set the following zones in Training Peaks:

    Zone 1: AeT-20% to AeT-10% = 136 to 152
    Zone 2: AeT-10% to Aet = 153 to 170
    Zone 3: AeT to Lactate Threshold = 171 to 177
    Zone 4: Lactate Threshold to maxHR = 178 to 200

    The following week, I went for a number of upper zone 1 runs and in the span of a week I got 3 notifications from Training Peaks stating that my Threshold had changed:

    New Threshold: 05:53min/km
    Date Set: 23/12/19
    Previous Value: 06:04

    New Threshold: 6:01min/km
    Date Set: 24/12/19
    Previous Value: 06:04

    New Threshold: 5:48min/km
    Date Set: 27/12/19
    Previous Value: 6:04

    Can anyone tell me what’s going on? As I am starting a new training block I really want my zones to be set as accurately as possible.

    What I’ve noticed is on road runs I am getting a massive discrepancy between the Rtss score and the HRtss score. It would be great to get them somewhat aligned if possible.

    Thanks in advance everyone!

  • Participant
    OwenFW on #35512

    What it sounds like to me is that you have not checked the box “Automatically apply new threshold changes” at the bottom of the Zones settings page, so you are receiving suggestions to make a change but they are not actually being applied. Otherwise it doesn’t make sense for the system to move your pace up and down like that over such a short period of time. If you do have that setting checked, maybe get in touch with TP support? They are very responsive.

    Someone correct me if I’m wrong, but I don’t think threshold HR and threshold pace have any connection in TP. If you maintain a new high average pace for 45 min, you will always receive a threshold change notification/suggestions, and when you maintain a new high average HR for 45 min, you will also receive a change notification, but the two have no affect on each other.

    Anonymous on #35546

    First, I would disable automatic threshold changes and notifications thereof in Training Peaks. It’s much more sustainable to test-set-train-repeat than it is to let Training Peaks calculate a frequently-changing generic result that may not be relevant for you.

    So I would:

    1. Test your AeT and AnT as we’ve described;
    2. Set your AnT in Training Peaks as required;
    a. Enter your AnT HR as Threshold Heart Rate and use hrTSS for workouts in variable terrain;
    b. Enter your AnT pace (if it’s been tested on a flat course) and use rTSS for road running workouts without any steep hills (usually grades of 5% or less).
    c. You can toggle the type of TSS used within each workout. So for a trail run in rolling terrain, set the workout to use hrTSS. For a road run, use rTSS.
    3. Train with those thresholds until you test again.

    Anonymous on #35547

    Wait… I just noticed you used 177 as your AnT HR. The aerobic drift test only estimates your AeT HR. Use the anaerobic test for AnT HR.


    1. Have you done an AeT drift test before? If so, what was the result?
    2. In the most recent test, how hard did 170 (at the start of the test) feel?

    jschoombie on #35562

    Hi Scott,
    Thanks for the replies – I am about to do the AnT test – with the holiday’s etc my schedule was a bit messed up so I thought I’d do the AeT test and then get the AnT test done soon after.

    Other than the above, I have previously done two AeT drift tests:

      Test One

    Date: 7th of January, 2019
    First Half Average: 148bpm
    Second Half Average: 157bpm
    % Diff: 6.08%

    I set the top of my zone 2 at 142bpm.

      Test Two

    Date: 5th of August, 2019
    First Half Average: 158bpm
    Second Half Average: 165bpm
    % Diff: 4.4%

    I set the top of my zone 2 at 154bpm.

    Regarding your second question, at the start of the most recent test the 170 was moderate. Towards the end I was having to work very hard and was bloody glad for the test to be over. It was much harder than the previous tests. I can’t say I am looking forward to the AnT test.

    Regarding the use of HRtss vs Rtss I always though it was advised to stick to one only, it makes sense though to distinguish between the flattish road runs and the trail runs. I’ll start doing this.

    Anonymous on #35590

    With respect to TSS, you could use just hrTSS for both. rTSS wouldn’t be appropriate for rolling terrain though.

    The reason that I asked about previous AeT tests is that I wondered if this most recent AeT test was close to your anaerobic threshold. It’s not unheard of to have an AeT HR at 170, but at that point, other tests may be more appropriate (lab or lactate). After you’ve recovered from the AnT test, I would do another drift test starting at 160 and see what you get.

    One difference between the two tests is that, with a drift test, your heart rate has room to go higher but doesn’t. In an AnT test, because of the duration, your heart rate can’t go higher. So at a Zone 3 intensity, it might be possible to think that the test was aerobic because heart rate didn’t rise when actually, it couldn’t.

    Does that make sense?

    Anyway, post your AnT results here if you want any feedback on it.

    jschoombie on #35878

    Hey Scott,
    I just attempted the AnT test and after a 15min warm up was only able to complete an additional 15min of the test before having to stop due to feeling like death was immanent (I’m probably exaggerating here…).

    Looking back now I probably shouldn’t have attempted the test as although I felt 100% I did have a 24hour stomach bug earlier in the week that may have limited my ability to complete the test successfully.

    Analyzing the 15min of data I do have, my average heart rate was 173bpm.

    I think it would be best to wait a week or so and re-attempt. In saying that, I felt it was more my muscular endurance that was the limiting factor at being able to continue the test not my breathing.

    Would it make sense to adjust the treadmill to 10% to reflect the gradient used during the AeT test?

    Pacing wise, in your opinion is there a target heart rate you feel I should try to hit at the start of the AnT test? I feel like my AeT and AnT may be very close.

    Anonymous on #35958

    If you’ve been sick, I would take at least a week, maybe more, to get back to normal. In general, we recommend one day of easy Zone 1 per day that you’ve missed. Really get back to training gradually.

    Because of your illness and the short duration of the test, I wouldn’t make any conclusions from the results.

    As I said above, I think you should do two tests:

    1. Another drift test at ~160; and
    2. An AnT test with a much longer warm-up.

    It sounds like your warm-up in this last test was too short and sudden. Take at least twenty minutes and be very gradual, even longer if necessary.

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