First Time AET TEST Help!

  • Creator
  • #49456


    I have just conducted an AET test with one of my athletes and just wanted to sense check my interpretation of the data with you guys. She ran outside for 60 minutes on a flat course and her starting HR was around 142. The average HR for the first 30 minutes was around 138 and for the second 30 minutes 140, The average pace for the run was 6:31km. Am I right in saying that this shows a less than 1% drift comparing the two halves and that this run was well under her AET? Should I re-test and get her to start at a slightly higher HR/Pace? It was also interesting that she said she felt like she could run forever so another sign this was well under AET.

    Many Thanks


  • Participant
    Shashi on #49460

    Was this test captured in Training Peaks? If you can make the workout public and share the link it will help.

    For outdoor tests, Pa:Hr in training peaks is used to check the heart rate drift. For indoor tests, when pace/incline is constant for the entire hour, we can compare the average HR for the first half and second half.

    jamesscott778 on #49469


    I use Final Surge so I’ve snapped the HR/Pace Data, does that help?


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    Shashi on #49477


    Thanks for sharing the screenshot. Sorry, I am not familiar with Final Surge but check if there is any metric similar to Pa:Hr (Decoupling). If not, you can try this –

    First Half:
    Calculate Avg. Pace: Let’s say it is 6:20 min/km (380 seconds/km)
    Calculate Avg. HR: 138
    Pace to HR ratio for first half = 380/138 = 2.75

    Second Half:
    Calculate Avg. Pace: Let’s say it is 6:42 min/km (402 seconds/km)
    Calculate Avg. HR: 140
    Pace to HR ratio for second half = 402/140 = 2.87

    Pa: Hr for the run = % change in Pace to HR ratio from first half to second half = (2.87-2.75)/2.75 = 4.3%

    For outdoor runs, when the pace is likely to change you will have to take into consideration the change in Pace as well to calculate the heart rate drift. So in the example you shared, drift is likely to be more than 1%.

    Check this Training Peaks article for a better explanation of the metrics.

    If the drift is less than 5%, then you can use the initial heart rate at the beginning of the test (likely around 138 or lower) as the AeT.

    Hope this is helpful.

    Anonymous on #49482

    Shashi is correct. Both HR and pace will vary, so assuming one is static will probably understate the drift (because in this case pace the pace likely slowed).

    If the pace were static (on a treadmill), then the drift in this session would have been 1.4%: 140 / 138 = 1.0144. But as Shashi noted, you’d have to include the first and second half average paces as well in order to really “get the drift”. 🙂

    An “all-day pace” might be under AeT. Not though that I’ve had clients with very low AeTs, so even though they were metabolically in Zone 3 at very slow paces, the muscular load was so low that it could have been an “all-day pace”.

    A Training Peaks premium trial might work if you want to really nail it down. Or include the average pace change as Shashi detailed.

    Shashi on #49527


    I have made some minor changes to the Pa:Hr calculation above. Scott brought to my attention that the way I used Pace in calculating the ratios was incorrect.

    Please let us know if you have any questions.

    jamesscott778 on #49551

    Hey Guys

    Thanks very much for your help with this!

    I can see that I was looking at this incorrectly, I don’t think final surge has the Pa:HR on it but I can set HR zones for particular athletes on there which this would be useful for.

    Thanks again


    sbr on #49567

    If you don’t have a TP premium account:
    You can upload the workout to Runalyze, which offers a Pa:HR calculation with its free version.

    felix.gottschlich on #50365

    Hey Folks,
    i did my first AeT Test for the 20 Week big Vert Plan.
    I estimatet my Target HR about 155-158 bpm because that where i could keep up nose breathing and felt good over the last weeks. The test was done on a flat coure but it was muddy. I think that 157bpm for the top of Z2 is a good estimation. but im an not sure if the result is significant due to the high variation in speed during the test. What do you think?
    The Link to the Workout in TP:

    Thank you,


    Shashi on #50373


    Based on what you mentioned, it would make sense to do the AeT test again. Allow your HR to stabilize at your target HR towards the end of the warm-up before you start the test.

    I would recommend starting a new thread as members and moderators will not see your question when you post under an old thread.

    Anonymous on #50432

    Quick correction. I’ll see new posts on new threads and any that I’ve responded to (like this one).

    FYI: If anyone wants to get email notifications of new threads, click the Subscribe link near the top of each forum topic page.

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