TrainingPeaks, the Aerobic Threshold and the Heart Rate Zones

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  • #8789

    I tested a few months ago in a lab and I’ve found out that my aerobic threshold is at 76% max hearts rate and the crossover point is at 83%. So based on that, my training in Z1 is at/below 76% and my Z3 is at/above 83%. I am using the 24 weeks mountaineering plan from Uphill Athlete.
    I had an workout today which triggered TrainingPeaks to send me a notification about changing the Aerobic Threshold to be 80%.
    While I understand that TP calculates TSS based on that, I am not sure if I should change my heart rate zones accordingly, so that my Z1 goes now to 80%.
    Could you please suggest what I should do?
    Thank you.

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    Anonymous on #8796

    Hi Florin,

    Training Peaks uses your anaerobic threshold to calculate TSS (not your aerobic) so you’ll want to enter the heart rate that represents the bottom of Zone 4. If you use your aerobic threshold, the TSS calculations in Training Peaks will be exaggerated.

    If you’ve had a lab test, I would ignore the Training Peaks recommendations (and notifications) and go by the results of your test. Training Peaks formulas will be generic, but your test will be specific to you.

    I hope that helps.

    Scott S.

    P.S. If it’s unclear from your test where the bottom of Zone 4 is, attach the test in a follow-up post, and I can take a look at it.

    florin_neagu on #8797

    Thank you very much, Scott. Here are my tests, attached. They lab made a mistake, which they corrected in the hard copy they gave me: my crossover point is at 149 bpm, which is about 83%. Also, I attached my TP Heart Rate zones. Do you see any changes I should make?
    This is extremely helpful.

    Thank you again.


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    Anonymous on #8805

    No problem. I’m glad it’s helpful.

    Although the crossover point is around ~149, I think you’ll get a more useful result by doing a DIY anaerobic threshold test:

    The heart rate you get from that test will be the one to use for your Training Peaks threshold. The TSS calculations off of that heart rate will do a good job of estimating fatigue.

    In general, I’d recommend that most of your training be below your aerobic threshold (“AeT”, “VT1”, ~136bpm). That’ll be the best way to raise your AeT. It varies by person, but AeT can get well into the 80% range. I think you’ll get the most bang for your buck by keeping your training below 136 bpm.

    Scott S.

    florin_neagu on #8806

    Hi Scott,

    Thank you very much for the insight. So essentially, I’ve been using the wrong number in TP and my numbers are not accurate. I will correct the mistake (I find the terminology a bit confusing in TP) but nevertheless, the progress is real and it is relative to myself, since I’ve been following religiously the 24 Week Expeditionary Plan.
    I’ve been training mostly at/below 136 bpm and I’ve done some Z3 around 150 bpm. Based on the numbers, is that correct? What would be my Z3?

    Thank you again,


    Anonymous on #8808

    Zone 3 will be between your aerobic threshold (“AeT”, “VT1”, ~136 bpm) and your anaerobic threshold (“AnT”, “VT2”, ~150???).

    Your AnT might be ~150 bpm, but I would do the DIY test to confirm. From your test, it was unclear to me where AnT was.

    When 99% of people (or businesses like Training Peaks) talk about “threshold”, they will mean AnT. In fact, if you say “aerobic threshold” to that same 99% of people, they will probably not know what you mean.

    Most people focus on AnT because it’s easier to identify (with a DIY test, time trial, etc.), it’s more gratifying because it feels like hard work, and it’s more relevant to short-duration sports (of two hours or less).

    But the AeT is more important because it’s what gives the AnT its power. And over long enough events (as in mountain sports), the AeT is really what matters, because it determines fuel economy, which is more important than intensity over long durations.

    Anonymous on #8809

    Also! If you’re using Training Peaks Premium and the Performance Management Chart, you can recalculate all of your TSS with one click.

    To do so:
    * Update your AnT heart rate on the Zones screen under Settings. Click Save & Close;
    * Go to the Dashboard, and click the menu icon in the upper right-hand corner of your PMC;
    * Click the Recalculate TSS button.

    If you don’t have a Performance Management Chart on your Dashboard, you can add it using the Charts Library icon on the upper left-hand side. Also, Steve just posted a tour of the PMC. You can view it here:

    florin_neagu on #8810

    Thank you so much, Scott. This is very useful information and I did what you suggested.

    florin_neagu on #8811

    If I recalculate and adjust as described here, it all makes sense now…

    s.luedtke on #8819

    Quick question guys:

    I just followed Scott’s steps to update ANT and threshold pace based on my recent lab test. I did the recalculate and my CTL just dropped from 67 to 51. Is this just mean that all along it wasn’t calculating correctly or did I just mess up and recalculate months of workouts incorrectly?



    florin_neagu on #8862

    I did the same and then I changed rTSS to hrTSS. Then I adjusted as suggested in this post:, starting with the first day of my training following the plan. And it came close to what I had before, unadjusted.

    Anonymous on #8891

    If your threshold heart rate before was understated–i.e. you were using your VT1 136 bpm value–then the training stimulus of your workouts would have been overstated, giving you higher TSS values than warranted and a higher CTL overall.

    Increasing the threshold number and recalculating will give you a more realistic CTL.

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