Interpreting blood lactate test. Also, zone definitions.

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  • #10618

    I have questions on two separate, but related topics.

    Zone definitions

    There have been several discussions on this forum, with (for example) insightful explanations about the detrimental impact about too much Zone 2 training for a highly-trained athlete.[1, 2] I think this is roughly correct:

    • Zone 1 starts at walking / jogging, and the top end of Zone 1 is roughly 10-15 beats per minute (BPM) below the top of Zone 2
    • Top of Zone 2 is the Aerobic Threshold (AeT), defined as the point where blood lactate increases above 2 mmol/L. Or when breathing through just your nose gets to be difficult.
    • Top of Zone 3: this is where definitions differ. Going by TftNA / Uphill Athlete, the top of Zone 3 is the Anaerobic Threshold (AnT), roughly where blood lactate increases above 4 mmol/L (although perhaps better assessed by average heart rate in a 30-minute field test [3]). Joe Friel, Andy Coggan, and others seem to split this Zone 3 into two, defining the top of Zone 4 as the AnT.

    Does it really matter very much, as long as most training is in Zone 1 / Zone 2, with very little sub-lactate-threshold / black hole (Z3 or Z4 depending on who you talk to), and some supra-lactate-threshold intervals?

    Interpreting my blood lactate test

    I performed a blood lactate test yesterday. No lab, just help from my very patient wife! Warmed up for 20 minutes, then took samples at 5-minute intervals with 1 mile-per-hour increases on a treadmill at 1% incline. See table and graphs attached.

    Looking at those numbers, I think my AeT is at roughly 173 BPM, and my AnT is at roughly 188 BPM. The delta between AeT and AnT is about 8%. My takeaway is that I should just focus logging more hours, mostly in the 150-170 BPM heart rate range. Does that sound about right?

    I’ve been fairly consistent this first half of 2018, building up to a couple of 20-mile hikes. But I’m not training for anything in particular at the moment, and volume is low (maybe 5 hours per week on average). I’d like to get faster at shorter distances (half marathon?), although focused on mobility and health primarily. [4] As an aside, Travell and Simons’ trigger point books have been super useful.[5] Six months’ worth of dealing with “sciatica” went away with three minutes of self-massage on just the right spot in my left gluteus minimus.


    [5] There are two volumes, upper and lower body.

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    Scott Semple on #22381

    Ack. I just went back up to the top and re-read some of these posts. I see that Scott J. recommended against using ~4 mM as a measure of AnT.

    To clarify my last post, I don’t use ~4 mM to define AnT, but as a proxy for it. I base all of my training off of AeT and percentages thereof, both above and below. So really knowing AnT has never been necessary for the way that I train. A proxy was close enough and mostly tested out of curiosity.

    When wanting to know race-pace-relevant paces, I used a specific test (on a treadmill because I wanted to be exact) similar to what Scott J. described.

    Reed on #22424

    Hi Scott,

    Thanks for the encouragement! Looking forward to adding a bit of time each week, over the coming quarters & years. I’m stoked to have had a pretty consistent 250-hour year, and from there I should safely be able to increase to 300 hours or so over the next year (maybe 350?). 20 hours / week would be fun.

    I’ve tracked speed alongside heart rate and lactate. See attached for my two most recent tests plotted like a Conconi test. Nice rightward shift of speed at lactate threshold, to about an 8-minute/mile pace from 9-minute/mile pace. It’ll be interesting to see what that looks like later this summer…

    I’ll do as you suggest, and test to higher lactate figures. I have not done a comparison of that treadmill step test with the “field test” (30-45-minute all-out run). That might be useful, too. Perhaps especially since I’d like to get faster at 10-20K distances, so having a clearer view of anaerobic threshold might be more important. That said, one of the lines that stuck out to me in Training for the Uphill Athlete was something like, “If you haven’t clocked 400+ hours of aerobic work each year for the past two years, that’s the biggest lever to pull.”


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    Reed on #36324

    Happy 2020! I don’t have any resolutions for the year, but I do have short update to share. I hope it’s helpful for anyone in similar shoes to me, balancing health / family / career / fitness. It has been fun seeing continued improvement even with the modest time investment I’ve been able to make.

    Over the course of 2019, I ended up with a nice round 225 hours of training. Mainly road running, some hiking, some strength, a tiny bit of AT skiing. 98% of my training volume was below aerobic threshold (AeT): 86% Zone 1, 12% Zone 2. I have been using, by the way, a 15-beat-per-minute wide Zone 2 in order to stay on the conservative / easy side. And my Zone 1 extends from ~165bpm down to ~125bpm – probably way too wide, but I found myself getting demoralized when jogging at a Zone 0.9 pace, so I decided to just give myself credit for Zone 1. 🙂 Others might benefit from separately tracking Zone 1 and Recovery.

    A lactate test this week showed that my speed at aerobic threshold increased by 9%, to 13kph to 12kph. That was gratifying to see! I’m not ready to run a marathon, but it seems that with that AeT pace I’m within striking distance (a few more quarters of training?) of a Boston-qualifying time. Both my AeT and AnT shifted up by 3bpm, to 183 and 196 respectively.

    I’ll be doing half (as a relay) of the Santa Barbara Nine Trails 35-mile race in March. Planning to add in a little bit of intensity, but not much – maybe 15-30 minutes of Z3 per week. I don’t have a need to peak for the race, but it’s a good catalyst for some different workouts.


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    Scott Semple on #36453

    Well done! (Again.) To get such good results on such low volume, I can’t wait to see what happens when you take a sabbatical and start training full-time… ???

    Scott Semple on #36454

    Also, I think a conservative rule of thumb for intensity above AeT would be ~3 minutes per hour of your 4-6 week average weekly volume. So a recent weekly average of 5 hours would be 15 minutes. You could bump that up to 30 a few weeks before a goal event.

    Reed on #36461

    Thanks, Scott! No sabbatical on the horizon, but I do hope to be able to devote another hour or even two per week, ramping up over the course of 2020. Glad to hear that my higher-intensity target is roughly in line with your rule of thumb. I think I know what to do (for now), now I just need to do it!

    Scott Semple on #36462

    Some sample workouts:

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