AeT Test, discrepancy RPE/Breathing/Lactate

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  • #42769
    Michael J.

    Hi everyone

    After an extended break from running due to foot/lower leg problems, I recently took up running again. I currently have no ambitions to race, my goal is just to be able to run/speed hike in the mountains for fun. During the last few years, I cycled regularly and kept a small amount of fitness. I am now determined to build a big aerobic base. I am doing about 6 days of training per week, alternating running and cycling. I can just cycle indoors at the moment, so overall volume is lower than usual, about 6-8 hours/wk.

    As I own a lactate meter (Lactate Pro 2), I am able to test myself regularly. But after reading everything I found on the internet and doing a whole array of tests on myself, I am more confused than ever about where to set my AeT HR.

    A normal test for me, on the bike or while running, will give about the following values (5min stages, readings in mmol/l)
    Rest: ~1.3-1.5
    Stage 1: ~1.3-1.5
    Stage 2: ~1.3
    Stage 3: ~1.1
    Stage 4: ~1.3
    Stage 5: ~1.5
    Stage 6: ~1.8
    Stage 7: ~2.1

    Seems easy enough, just stay below the HR after stage 7. However, training at this level (~142bpm on both bike and run, incidentally my “uncorrected” MAF heart rate on the bpm) feels pretty hard. I can’t nosebreath only anymore, get significant HR drift after a relatively short time and don’t feel recovered the next day. My “feel good” intensity is about 10-15bpm lower, incidentally at the point where my lactate readings reach the lowest level of the entire test.

    I somehow can’t believe that I am at the point where I have to train in Z1 mostly, since I am clearly aerobically deficient (slow AeT pace >10min/mile, more than 10% spread between AeT and AnT 142/165). I feel I should be able to train much more right below AeT, but it seems to destroy my legs and it makes me tired, moody and gives me bad sleep after just 2 or 3 days.

    So why is it that lactate/RPE/breathing differ so significantly? Could it just be a case of too little muscular endurance? Do I just have to suck it up and be tougher, train through the tiredness and sore legs?

    With the running, I am seeing at least a little progress from week to week while training in Z1, but progress on the bike is pretty much non-existent at this time…

  • Inactive
    Anonymous on #42771

    Do you get the same results with lactate and heart rate for both cycling and running?

    That would be pretty unusual. More typical is for cycling heart rates to be 10-15% lower than for weight-bearing sports.

    Anonymous on #42772

    …and because your testing is individualized, forget about MAF. That’s a generic formula that works “on average”, which means not very well IMO.

    Michael J. on #42777

    Thank you for your response. I know it seems unusual that I get about the same results for running and cycling, but I think this is just because I haven’t run regularly the last 4 years but have cycled about 350 hours per year, so I should be much better trained in cycling. I would expect the relationship between cycling and running HR to change somewhat as I get fitter. Max HR for Bike (185) and Run (188) are still very similar, so I wouldn’t expect too much of a difference in training zones anyhow.

    So do you think I should go strictly by lactate results and try to train as often as possible in Z2 near AeT/2mmol (which certainly won’t be every day) and just do the rest of my workouts in Z1 every week? Maybe I could start with just a few minutes Z2 in the middle of 2-3 Z1 workouts a week and get more durable with time, so HR drift and muscular fatigue would become less of a problem?

    Anonymous on #42812

    A few things:

    since I am clearly aerobically deficient (slow AeT pace >10min/mile…

    ADS has nothing to do with pace, just the relationship between the two thresholds such as…

    …more than 10% spread between AeT and AnT 142/165.

    AeT does seem low relative to AnT, so I’m not sure why the RPE would be so high and the sessions would be so fatiguing.

    Is the RPE the same for both running and cycling at the same heart rate?

    Either way, yes, I would train where it feels easy. Based on your maximum HR, it’s conceivable that you could raise both thresholds. I wouldn’t be surprised if AnT rose to 170 and AeT rose to 155 or higher. That will take time and patience though.

    Anonymous on #42815


    To supplement what Scott S has said above and to answer your latest question I’ll jump in to this conversation.

    I’d trust the lactate reading much more than I would nose breathing or MAF. The blood lactates you show are a window into your personal metabolic response to exercise. However if your perceived exertion is high at 142 and you do not recover from day to day then that is also a very valuable personal feedback that training at 142 is just too dang hard for you on a daily basis. It is possible to have ADS and still have a PE that is too high at your AeT HR. It’s rare but not unheard of. I would conduct most of your base training in Z1 10-15 bpm below 142 and do 1-2 sub 60min Z2 runs a week. This will help improve your running economy. After 4 weeks of that begin to add pick ups to those Z2 runs for further gains in running economy.

    I hope this helps,

    Michael J. on #42818

    Big thank you for both of you, I really appreciate your responses. I reread the chapters on Transition and Base Phase training and now think, I probably did too much too soon, even if my zines are set properly. I will restart my plan with a proper transition phase for the next 6-8 weeks according to your suggestions and the example training weeks from the book. My goal for this phase is to slowly increase my tolerance for weekly time in Z2, starting, as suggested, with two relatively short Z2 workouts per week.

    Thank you again, I’ll keep you updated.

    Patrick on #42860

    Hi together

    What about taking “Stage 4” or “Stage 5” or even “Stage 3” as AeT since at this level lactate begins to rise (above rest)?

    I’m just reading the manual of Swiss Olympic:
    On page 89 you find an example of a lactate test. The authors define AeT (AeS in German) not where lactate rises above 2mmol (HR154 in the example; interpolated), but where lactate begins to rise (HR133). The difference is quite big. The authors recommend aerobic endurance training at HR120-135 (~Zone 2 at uphillathlete), whereas HR135-150 they call speed training (~Zone 3) and HR150-160 training for LT (~Zone 4).

    Michael, how feels training at these stages? At Stage 7 you’d probably be where Swiss Olympic considers your effort as training for rising LT…

    Anonymous on #42864

    I would love to read that. Is there an English version? I noticed that the end of the URL has “DE”. That made me wonder if there’s a version that ends in “EN”?

    Patrick on #42874

    Hi Scott, I noticed that, too, and tried. Unfortunately it didn’t work. But I just wrote an email to swissolympic to ask if an English version exists. I’ll tell you when I’ve got news.
    However, the example you will probably understand also in the German version.

    Michael J. on #42875

    Hi Patrick

    I have found the same the same manual from Swiss Olympics sometime ago (I’m Swiss). I even read pretty much every open access study I could find on FatMax, AeT etc. But reading all this stuff just added to my confusion in the end since there is so much conflicting information in the studies, especially concerning measurements/calculations of FatMax/AeT/AnT. BTW Beat Knechtle, another Swiss, has done a lot of studies with different subjects of all ages, abilities and metabolic capacities.

    Somehow, after reading all I could find on the subject, I came back to where I started from, TFTNA and TUA. These books restarted my desire to go out and run/hike in the mountains and there are many success stories out there – and no magic pill endorsement at all, just the simple message that intelligent and consistent work and dedication will pay off. So I started this thread to stop oberthinkining the whole thing and start doing the work…

    @Scott Semple
    I’m afraid I couldn’t find the Swiss Olympic manuals in English, but I’m quite sure they exist somewhere on the web.

    Some of that information should be comprehensible for non german speakers, too, especially the sample test results (“Laktatstufentest Beispielauswertung).

    Patrick on #42880

    Hi Michael,

    thank you for your explanations. I also studied a lot of books and material on the subject and see that there are some conflicting theories. I try to integrate them in a way that fits good for me. Hence I’m experimenting a bit to find my personal way.

    For a while I’m considering buying a portable lactate meter, but here in Switzerland it’s so expensive. When I stumbled over your post and then coincidentally over the manual from Swiss Olympic, I thought “hm, if in the end the results I get with measuring can be interpreted so differently, maybe costs are too high to get them”.
    Do you have a lactate meter, and if so, which one, and maybe you can tell me where to best get it? How much do you use it? Or do you have your results from a lab?

    I’m still interested at which of your stages now you train most of the time, what stage you take as AeT.

    Michael J. on #42886

    Hi Patrick

    I instinctively tend to work out right around that lowest point on the lactate curve, give or take a few bpm. I can hold that pace/power for several hours (on the bike at least) with minimal HR drift and I am usually recovered within 24 hours. Since my progress has stagnated for some time on the bike, I suspected that maybe this intensity is a little bit too low (lactate between 0.9 an 1.1 usually) so I tried to train more often near 2mmol, but I probably did too much too soon and was digging a hole for myself.

    I bought the Lactate Pro 2 several years ago online, but can’t remember where at the moment. It works very well for me, especially if you take all the precautions listed in the article on this page. The test strips are quite expensive however.

    I used it very regularly in the beginning, but my heart rate zones tended to be very stable over time, so I used it less and less. I never experienced a significant rise in “AeT” heart rate, which was another point that made me rethink my base training intensity. The point right before the first rise in blood lactate seems to correspond nicely to the top of Z1, as it lies pretty much exactly 10% below the 2mmol point.

    Anonymous on #42893

    As I understand it (and from what I’ve seen as a coach), lactate at AeT can vary between 1.5 and 2.5 mM*. An RER of 0.85 may or may not coincide with that first inflection point. And FatMax may not either.

    The important thing is not to get too caught up in trying to be precise. Base-building doesn’t have to be done right at your aerobic threshold. In fact, lower is often better.

    * From what I’ve seen, slow-twitchers often have lower lactate at the first inflection point (i.e. AeT) and fast-twitchers have higher. For example, I’m on the FT side, I’ve tested myself a lot, and the number of times that 2.3 mM coincided with my AeT HR is spooky (and often happened within one or two beats).

    Patrick on #42902

    Thank you very much for your clarifying answers. They helped me a lot reaching a (momentary) conclusion.

    Michael, you mean this page?
    As I understand, the main thing to rise at AeT is performance. The more aerobically deficient the athlete is, the more rises also HR, which seems to be no matter for both of us, I don’t expect too much rise of HR at AeT.

    Scott, hearing that lactate at AeT can vary across subjects really helps for understanding. This means, I have to consider the whole picture instead of relying on a single value. I’d guess I’m more a “slow-twitcher”, so am ready to set AeT below 2mM.

    Then it is however not the most important thing that AeT is set exactly on the right spot, but to do high volume especially at the point where lactate begins to rise to flatten the curve (Z1). Further do some training in the area where lactate rises (Z2), till up to AeT as defined here at UA and only so much as my body likes, bearing in mind that perceived effort should be light to moderate, motivation to hold the pace for hours is high and recovery quick.

    I also take from both of your statements that measuring lactate is really a nice thing. So I will strive to get a device.

    In the meantime, I’ll do the following, derived from quite a lot of experience, integrating quite a bit of studies including every bit of information at UA and extensive data collecting with HR belt:
    Long sessions (3hr ascent):
    1. Start slowly. [HR 115-125]
    2. After 15-30 minutes I add a notch of speed to what I know from experience is my sustainable pace and hold that. (I have no problem holding that pace for 3 hours and then day after day) [HR 130-135]
    3. For the first hour at sustainable pace because of HR drift I see rising HR. Average of second half [average HR 140] of that first hour is 3.7% higher than first half [average HR 135]. [HR after an hour at sustainable pace is a little bit above 140]
    4. HR keeps on rising during the second hour, but always remains below 150. During the third hour HR can increase to 156-160 and then remains stable if I continue (getting slower..).
    This should correlate quite well with Z1 training.

    Short sessions of 1hr ascent: I do warming up of 10minutes then accelerate to HR 140-145 and hold that pace. After 1hr HR is about 150-155 and average HR of second half still less than 5% higher than average of first half after warming up.
    This should still be comfortably within Z2. I can nose breathe the whole time, could hold on for another hour without any problems and it doesn’t feel hard at all, for that I have to push above HR 160 (Estimated AnT is about 165-170).

    That intensity goes very fine for my body, I recover quickly and can do it for several days. And it is fun and does definitely feel activating, unlike HR 115 (where HR drift is zero and I’m severely bored). I’m quite curious to see where my training fits in the picture of the lactate chart, though now that I reached this conclusion it doesn’t seem absolutely necessary to get the numbers anymore. Anyway, as soon as I’ve got them I’ll tell you.

    Hope that’s useful for somebody.

    Interested in hearing what you think. Enjoy your sessions 🙂

    Anonymous on #42909

    Super. I think you’re on the right track.

    I’ve often wondered if all sessions where intensity is measured by heart rate should be progressive (where the target HR rises with duration). The problem with it is that it can easily trigger a self-serving bias where we convince ourselves that a higher heart rate (and greater gratification with the increase in speed) is still under the aerobic threshold.

    In contrast, going by heart rate and slowing the pace has a much better chance of being under the aerobic threshold and with much less potential downside.

    If you want to try training using progressive heart rates for base-building sessions, I would test your drift on a treadmill first. Find your AeT pace in a drift test, and then hold the pace for several hours and see how much heart rate drift you get. Then use that amount of drift in subsequent workouts. (And bear in mind that temperature and hydration will impact your heart rate as well.)

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