AeT Adventures: Freak finger lactate but nose breathing & HR drift validation? | Uphill Athlete

AeT Adventures: Freak finger lactate but nose breathing & HR drift validation?

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  • #36708

    Hi all, I’ve always been one of those guys that’s never trained (more fool me) and just gone climbing instead. However, my circumstances are changing and I’ll not have the luxury of being able to run off to the mountains anywhere near as frequently as I used to, so I thought I should look into training instead as a way to preserve my sanity.

    I’ve recently read TftNA (and loved it), and as a result have been putting together the framework for a training plan based on the guidance within, augmenting it with the trove of information found on this site and the forums.

    Naturally, first place to start seemed to be an AeT test to ensure that I did my training in the right zones, but that turned into a bit of an adventure that I thought might be of interest for some people here considering what tests to do and how their results compare between the different methodologies. I also have a few questions of the back of it all. (Sorry in advance for the long post.)

    A few personal details to start with for context (if it helps):

    Age: 32

    Gender: Male

    Weight: 81kg

    Training history: None (active but never trained, but 10+ years of relatively low intensity long duration physical work)

    RHR: 44

    Max HR: Never tested but have hit 201 in runs before

    LTHR: According to Garmin 183, however I have averaged ~190 on runs more akin to the 30 minutes max effort test Scott has suggested elsewhere.

    Alpine Combine 40cm box step result: Poor (40:35 – I used slightly too much weight, 24% rather than 20%, but even if that tipped me out of the “good” range it would still have been a “bad” good result)

    HR monitoring device: Garmin Fenix 5 w/ chest strap (always)

    AeT Test 1

    To get a ballpark figure I tried the nose breathing treadmill test detailed here:

    Indoor DIY Guide to Determining Your Aerobic Threshold: Treadmill Test

    And got the following results:

    HR 178 @ 6.4kmh @ 10 degrees

    My first impressions were that it was a suspiciously high heart rate and not very fast, but I felt good afterwards and didn’t really expect it to be fast as I expected to have ADS.

    Later, when trying to work out the scale of my ADS using the 10% test and the Garmin calculated AnT HR of 183 I got a value of 2.7% which, nice as it would be, seemed highly, highly, unlikely.

    Even using my AnT HR estimate of 190 based on max sustainable effort for 30 minutes gave me 6.3%, this also seemed too good to be true. However, it’s also quite possible my AnT HR is higher because I wasn’t specifically trying to test it/sustain max effort on those runs (could walk, didn’t need to vomit after etc.). I also have no idea what my max HR is so although 190 seems very high, it might not be relatively if I can hit 201 without specifically trying to max out.

    Based on these too-good-to-be-true results, combined with the fact that Scott has previously expressed caution about the accuracy of this test for people with ADS, I figured I should try something more reliable.

    I was a bit anti doing the HR drift test because I predicted that would likely turn into a trial and error exercise with hours of running inadvertently in zones I should not be training in – something that I felt I should avoid given my suspected ADS, so I bought a lactate monitor instead (I’m also a bit of a data geek, and as a paramedic I like medical toys).

    AeT Test 2

    Newly procured lactate monitor in hand I did a fasting test on waking and was greeted with a result of 8.5mmol/L. Not good. Very not good. It would seem I have no AeT, or Zones 0, 1 or 2.

    I repeated various tests throughout the day and they were all pretty shocking, I even manged to get a result >22.2mmol/L after a 40-minute Transition phase General Strength workout.

    I’d read about Extreme ADS, but I’ve never done cross fit and don’t have a history of HIIT training. Granted, on the few rare occasions I ran, I ran too fast, but that was probably only about 20 times a year and clustered into a few intense weeks with massive lapses in between rather than anything I would have imagined sufficient to engender such extreme changes to my physiology.

    A little experimentation later using alternate test sites and getting normal resting results of 0.7-1.3mmol/L (earlobes and even cannulating my forearm and using venous blood), and then experimenting with ways to vasodilate my hands using hot baths before testing which also produced more normal results, it appears I actually likely have a previously undiagnosed circulatory problem with my fingertips that renders them incompatible as a test site – they are just almost always too hypo-perfused to give a value indicative of my systemic circulation.

    This is likely very rare, but thought it might be something for people to be aware of as “a thing,” and to be sure to check a secondary site (like earlobe) prior to assuming they have diabetes or HIIT induced Extreme ADS if they get freakishly high readings.

    AeT Test 3

    My newly procured lactate monitor now +/- useless (its hard enough to DIY an earlobe test whilst standing in front of a mirror let alone whilst running, and I figured trying to draw venous blood on a treadmill is a good way to get kicked out of the gym) I figured I had to suck it up and do the HR drift test and got the following results:

    Warm up, 30 minutes, walking slowly increasing to test HR and pace – 178 bpm @ 6.4kmh @ 10 degrees (avg HR 132)

    Lap one, 30 minutes @ 6.4kmh @ 10 degrees (avg HR 179)

    Lap two, 30 minutes @ 6.4kmh @ 10 degrees (avg HR 183)

    Cool down, 5 minutes @ 5kmh @ 0 degrees (avg HR 149)

    This (if I’m correct) gives me a HR drift of 4 beats, ~2.2%, and would mean it was conducted within my AeT?

    I felt pretty good after and a few minutes later found a mirror to do a lactate earlobe test and got 2.1 which seems to reasonably back up the HR drift results? Sadly I didn’t check before to know what my baseline lactate was, but I had got 1.7 from my venous circulation about 1 hour after breakfast and had also had lunch and fairly recently eaten a snack before this test.

    A few questions for the forum gurus:

    Based on the above tests do you feel it is reasonable for me to set my upper limit of Z1 at 160 (90% of HR drift test target) and upper limit of Z2 at 178 (100% of HR drift test target) or should I pick a more conservative value?

    Do you feel there is much benefit in me pushing to obtain a more accurate AnT value? I guess it would help define Zone 3 for later down the line and confirm where I sit on the ADS scale for progress mapping?

    Now that I have AeT (hopefully) nailed down and other ways to find AnT, am I correct that finding my Max HR is +/- irrelevant? (The prospect of those tests honestly does not “spark joy”)

    Thanks in advance, and I hope that my experience with the lactate monitor was at least interesting for some.


  • Inactive
    Anonymous on #36728

    Sorry, I tried but… TMI. You’re right. It’s a long post!

    Can you condense it into five sentences/questions?

    tonybelgrave on #36732

    Please see attached stats of workouts (left is from 15mins of nose breathing after slow warmup and right is 1hr at same pace for HR drift after a 30 min warm up)


    It looks like 178 should be good to use as my AeT?

    Getting an accurate AnT at this stage is only really useful for assessing ADS/future progress as all training will be in Z0-2 for the foreseable future anyway?

    Max HR test is irrelevant other than as a curiousity if have AeT and AnT dialed?

    Thanks Scott 🙂

    You must be logged in to view attached files.
    Anonymous on #36738

    I think you’re on the right track.

    1) High-170s is higher than average, but not unheard of. And you were at 2.1 mM a few minutes after the test. Again, higher than average for AeT La, but not unheard of.

    2) How recently was a 30′ run at 190? If recent, then you could use that as AnT. If not, you may want to re-test.

    3) Max HR (like VO2 max) does not inform training much. But both are good for cocktail party chit-chat!

    tonybelgrave on #36757

    Thanks for having a look at it for me, I was also initially quite skeptical about the 178 AeT from the nose breathing test, but I guess the 2.2% HR drift from the 60 minute test and a non-fasting lactate of 2.1mM seem to suggest its probably not too far off.

    Fair comment on the 190 AnT test, was almsot a year ago, will retest.



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