HR Drift Test still a problem.

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  • #33435

    Hi Guys,

    Sorry to come back to this topic but though I would share for comment. It regards walking Heart Rate Drift Test on treadmill.

    Before I get into the detail, let me state up front that I’m 100% behind the methods developed by the Uphill Athlete team. I’ve stuck rigorously to the AeT training methodology over the past 3 months: >100 hours with 25% Z1, 65% Z2 and 10% Z3. Most of the Z3 has been just above AeT or from an AeT test. I train 6 days almost every week and get 1, occasionally 2 days outside in mountains each week. I’ve only ever felt fatigued a couple of times and have never finished a session exhausted. I do a 1 hour active recovery dog walk most days in addition to above. As a result my fitness has increased significantly – at nearly 64 I’m moving across the mountains as easily I ever have in 50 years – constant pace, don’t need to stop or fuel, HR on or below AeT >95% on the uphills and my pace on a par with my previous best, and I could easily go faster. UA methodology works, but then you already know that.

    Now the issue. After an initial AeT I set my AeT at 110. Trained for a month then retested – drift was 2%, posted on the Forum and Scott (Semple) suggested increasing to 120 – great. So trained for a month at 120, re-did AeT and drift was 7%. Retested a few days later and it was 5% so decided to hold at 120. So, after 2 months at 120, I retested again today – drift was back to 7%, although pace has really increased over the period. To get my HR to the AeT starting point of 120 I warm up very gradually over 15-20 minutes to 3.5mph at 12% gradient for the test and that’s my issue – that speed and gradient is pretty close to my limit, not cardio wise but physically. Could there be a neuromuscular effect upsetting the test results? I know if I stick to an AeT of 120, that I’m going to struggle to physically walk at a rate/gradient to get it to the starting point of 120 in 4 weeks time. Note that the treadmills I have access to have a max gradient of 15% – I’ve found that 12% at 5.6kph is the “easiest” balance between gradient and speed and pretty close to my limit. (During training I set a gradient between 10% and 15%, and vary speed to hold HR on or slightly below AeT)

    A thought. As a retired scientist/engineer I like to analyse things so have looked deeper into the physiology behind the results. The 3 tests I’ve done at 120 AeT have all gone well into Z3 – around half way to my AnT. At that HR my anaerobic metabolism must be kicking in to help the aerobic side, although I’m still perfectly comfortable fatigue wise. When I look at a “good” AeT test profile the gradient of the slope is consistent for the full hour of the test as would be expected from a linear drift. When I look at the 3 “bad” tests, all of them flatten out early into the second 1/2 of the test which I’m guessing is where he anaerobic side has kicked in. Could this infection point be a better indicator of my actual AeT than sticking with the 120 (or even reducing it) for a third month. Does the consistent linearity of the gradient prior to the inflection point indicate that I’m still in aerobic zone? I really feel I can push my AeT higher, but equally don’t want to erroneously move into the “happy hard” Z3.

    Apologies for long note – any advice most welcome.


Posted In: Ski Mountaineering

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    Anonymous on #33457


    You and I are in the same boat when it comes to AeT. We’re old! We are not going to see much increase in HR as our AeT improves. At our age our HR reserve: The distance between resting HR and MaxHR is greatly reduced from our youth. I’ll use myself as an example. My resting HR is about 50bpm now. When I was in my 30s and training more and harder it was 40. Now I can’t handle nearly as much training load and I suspect that’s the biggest reason it is higher. The cardiac muscle is just not getting enough training stimulus. In my 30s my max HR was 185 (remember there is a huge interpersonal variation for maxHR) Now I would have to do some serious damage to hit 160 (my 35year old self had an AnT of 165). This is just one of the many benefits of getting older. It explains why we can’t run as fast or as far as we once did, let a lone jump as high. Now a days my AeT is typically about 130 (some especially good days It will be up at 135+ and on some days when I am tired it’ll be around 125. In my 30s my AeT was 155.

    So, you might have gotten as much AeT HR change as you are going to get. But, much more importantly than HR is pace at AeT. You’ve seen significant changes in your pace and that is really what matters. That’s a fair measure of performance and isn’t that what we’re really after?

    These tests are not infallible because we are not machines and it is hard to recreate the same conditions each time. You can see the same thing even with laboratory gas exchange tests. As they say; “results may vary”. The HR drift test seems to correlate very well with both GET and blood lactate tests when we have tested them back to back.

    In short I think you can forego more HR drift tests. In stead I would continue to watch and relish the improvement in pace and effort at 120HR. Here is whatI recommend: Do your own little AeT time trial. Find a nice long hill or course you use regularly and test yourself there using 120 as the upper limit. Find some convenient landmarks at 30-45-60 min and note your improvement from time to time. Don’t cheat and go over 120 for any appreciable time. As few seconds is ok but not a few minutes. A performance test like this will be much more informative.

    Another depressing note about aging to consider: I have noticed that the older I get the harder I have to paddle just to stay in the same place. Improvements in fitness and performance come much slower and require much more work than they did 30 years ago. The take away for older athletes is: DON’T STOP.

    I hope this helps.

    derekosborne22 on #33532

    Hi Scott,

    Thank you. Thank you on two counts:

    1. For taking the time to respond so fully – it did not take you a passing two minutes and is very much appreciated.

    2. For the very realistic appraisal. You’re right – I’m not as young as I once was and was getting carried away by the improvements gained so far. I was making two fundamental errors – firstly I wanted to work “harder” to continue the improvements, and secondly I was “self coaching”, trying to fit a rationale around the test results to justify moving my AeT up to 125 or maybe even 127. You very rightly stepped in as a good coach should and reset my mindset and expectations – thank you.

    We are quite alike in some ways: my resting HR is 50; working at 160+ these days requires considerable effort (I haven’t been anywhere near 160 since I started UA protocol – honest). We differ as well though: I had no idea what a HR monitor was in my 30’s, never mind my max HR or AeT. Indeed in my 30’s I was so focused on career and family that exercise was an occasional distraction, and training was zero. It was the classic mid 40’s mid life crisis that kicked it all off again and I haven’t looked back. I can’t compare where I am today with the past, but must be close to the fitness I had in my late teens, early 20’s when doing big routes in the Alps.

    So, I reset my AeT back to 120 this morning (I had kicked it up to 123 10 days ago), did 90 minutes on the treadmill this morning and it was nice to be back at that easier effort. I’ll replace my planned AeT tests with your suggested pace test. In the end I was too focused on the number and not the output and goal: my ability to move through the mountains is better now that it has been in a long time, maybe ever. It’s made it more enjoyable and relaxed – I now reach a summit and instead of “that was hard work” now say, where’s the next summit.

    It really is more sincerely appreciated.

    Thank you Scott.

    Anonymous on #33611

    Thanks for the kind words.
    For the next step in your training I suggest that you conduct our DIY AnT test (see the article by that name on our site. Then set that as the top of Z3.

    For us older folks we can’t relay upon the 10% rule (the spread between AeT and AnT) to determine when to add intensity. With the good progress you’ve made in aerobic base pace improvement you should now begin to feed in some intensity 1 day/week. Start with Z3 and something like 3x6min with 2min recovery between. This is easy to control on a treadmill. As you feel yourself getting stronger begin to add more volume slowly so you do 3×7 then 3×8 then 3×10.

    Once you are at 3×10 it is time to add some Z efforts. Do this by starting at 4x2min and again slowly build volume in Z4 but keeping each repetition under 5 min. Start with 1x/wk and reduce the Z3 work volume by 2min for each min of Z4 you add.

    In a few weeks you will notice some real gains. Keep all other training to well below 120 Use Z1 to around 110 for almost all aerobic base workouts between these harder sessions.


    derekosborne22 on #33644

    Thanks Scott,

    I definitely feel I can add some intensity, particularly now I’m maintaining AeT at 120 so above is good for me. I will also do a AnT test next week – will be interesting to see result and how it compares with my spring/summer road bike HRs where I could sustain an average of 148 for around an hour of close to max effort before hitting the wall. For clarity, do I maintain Z2 sessions during the Z3 phase or should these move to Z1. When I introduce Z4 sessions, do these replace the Z3, or do I do both 1xZ3 and 1xZ4 per week, and make the rest Z1?

    On a more general point, the key objective of this training is to prepare me for a tough 10 day hut-to-hut tour end April next year. Tour will be at 1500-3000m altitude for duration, with three consecutive 12 hour days. Reasonably heavy pack and we will be carrying skis at some points. My current plan going forward is summarised below so question: given this April objective, do I introduce your suggested Z3/Z4 sessions now or continue Z2 base building with some ME, and add Z3/Z4 for last 2 months prior to trip?

    Dec: 5xZ2 per week, adding duration and vertical week by week with 1-2 6Hr+ hill days per week with pack approx 10% of BW. Introducing 1xME session based off advice in book/this site (Note: 3 week increasing, 1 week lighter cycle)

    Jan: As above, but with 2 weeks planned downhill skiing end Jan/early Feb in Alps – mainly piste based as with family and friends, but intend to try a fit in a daily Z1/Z2 30-45 minute jog to maintain base.

    Feb: On return for alps, major move up: 1xZ3 session, 2xhill sessions of 6-7+ hours each with 15% BW pack. No ME, and everything else at Z1

    Mar: as per Feb, but increasing Z3 intensity and moving into Z4, and pack going to 20% BW. Hope to fit in a week at altitude (Alps) end of March which will have 3-5 skinning sessions of between 2-5hrs each, plus some easy piste skiing.

    Apr: as per Mar for start then tapering down for last 10 days.

    Comments much appreciated, then I’ll leave you in peace 🙂

    Many thanks,

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