Lactate Testing - Data and Results

But who is using lactate or gases to calculate speed :man_shrugging:
a better analogy would be to work out the Power or fuel used by the car.

speed & distance would not tell you what is going on under the hood anyway.
Terrain, aero drag & rolling resistance would have an effect on speed but not what is going on under the hood.

Coincidentally, my high school physics teacher would periodically measure the 0-60 mph time of his car. When it rose above a particular point, that’s when he knew it was time for new spark plugs.

Not quite so facetiously, 6 min walk distance is routinely used in clinical research as a measure of cardiorespiratory fitness. In fact, I know somebody who is presently funded to the tune of millions by NIH to determine whether a novel treatment improves 6 min walk distance in a certain patient population. He’s previously demonstrated that it improves VO2max, but that isn’t considered good enough to change medical practice.

TL,DR: The best predictor of performance is performance itself. For athletes and coaches, “looking under the hood” to determine how that performance is achieved rarely provides actionable intelligence.

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Does anyone own a lactate meter that they use for testing? I am considering getting one, rather than upgrading my (decent yet boring) aluminum bike. I get that the test strips are expensive, but the cost of the meter and (self) testing would be less than hiring a coach.

It seems to me that the first threshold where we switch from FatMax to majority carbs and the second inflection point at threshold where there isntoo much lactate or hydrogen in blood to tolerate increased power are really the two metrics that most coaches/plans are trying to work from or approximate through the use of watts and HR. Everything I read and listen to lately seems to reinforce the fact that the watts and HR outputs are being used as proxies for these two lactate levels.

Does anyone use a LM to test their zone 2 watt/hr at begining of zone two workouts? Has it helped?

Does anyone use the second lactate threshold to guide intensity intervals while doing a TR workout indoors?

I get that there are other intensities to do, but i could experiment with SS after making sure that I am in Zone 2 for 60-90 minutes, or taking a day off when HR is too high for z2 lactate, for instance.

I listened to a TPeaks pod recently in which they recomend using 5-10 minute ramp levels while self testing with a lactate meter, so that HR and Lactate can settle to a representative level, rather than getting artifcially low numbers because 3 min ramps don’t allow HR and Lactate rise to the new plateau of the recent intensity.

This self-test would probably cost $10-15 in strips and coukd be dine every few weeks to set HR and Watts levels. Then, a daily z2 check with the LM would be about $5.

The meter is $550ish. Does anyone go this route instead of hiring a coach, or as a way to guide intensities in a TR plan? In other words, does anyone adjust intensity of TR workouts after lactate testing the important work rate in a given interval from TR, whether endurance or yhreshold, or VO2?

Thanks for any input in advance. Want to focus on doing base and losing weight gained while sedentary for 5 years following years of racing in my youth. It just seems like this is the way to make sure training is doaled and to make sure metabolic health is decent.

Have one and used it for testing quite a few times. Found the data interesting but not especially useful and not something you can only get from lactate.

There’s more than a few comments saying that they got no useful information out of lactate testing so I’d just make sure to do your research.

I thought about getting one, especially when the ISM fad was at its peak, but in the end was convinced otherwise.

There’s no switch. It’s a continuously variable system. Even with lactate tests, a range is identified not a tipping point. Also, you don’t have to ride at “fatmax” to improve “fatmax”. You just need to do more endurance paced riding. It’s really simple and doesn’t need to be complicated with lactate.

It’s really easy to test one’s FTP and that’s free. For the lower point, I just ride in my WKO5 derived zone2. ISM’s 2mmol lactate zone2 is probably closer to tempo anyway. Ok, so ride some tempo if that is in your plan. I just can’t see paying for a meter and the strips to figure what is already easily figured out. And FWIW, since ISM is really vague on training prescriptions I wouldn’t follow anything he says. The only message I get from his is to ride more endurance. Ok, check - I already got that down.

If one wanted to monitor these kinds of levels daily and/or in real time a Moxy (NIRS muscle oxygen sensor) would be the way to go. Some coaches have completely switched from lactate testing to NIRS because it’s a one time cost and the athlete can use it every day.

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Per the comment pointing out this existing topic, I moved your post and the direct replies into that same topic. There is plenty of prior info to review in addition to any new replies added.

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I too would vote for a NIRS sensor over a lactate analyzer, but only for testing purposes when measuring actual performance isn’t possible/ideal (e.g., injury, too close to important competition). I don’t really see any benefit to training with one.

thx, I am new here.


Part of my interest in LT1 is for metabolic health. As an overweight FORMER cat 1 cyclist with a family history of type 2 and evidence of some insulin resistance in my 40 year old body, I want to make sure that I make the metabolic changes needed to increase mitochondria as I come off the couch. I care about pushing LT1 up in order to encourage my body to prefer fat as fuel for regular rested living because I think it might curb over eating derived from blood sugar peaks and valleys resulting from insulin resistance. I also want to do the ISM training and get the work at FAT MAX done and get faster at low HR. But that is secondary.

Does anyone with the metabolic goal have input to that end? Also trying to maximize volume because I happen to have time for the next 6 months and want to drop weight and build base for further training in years to come. Any input on that would be appreciated. I have 10-15hrs a week, but only for the next 6 months, and then back to 8-10.

The problem with a NIRS device is that it really doesnt tell you anything, until it tells you everything…
The daily variations in SmO2 is quite big, for me cycling it ranges from 85% to 75%. Does it give me realtime feedback of lactate? Yes, but no. You have to look at the sloperate to have some understanding of it. That means you have to use many parts of your brain while biking :stuck_out_tongue:
But after using my Moxy for 4 months, combined with a lactate meter I have a good understanding of what rates gives what values, and at what intensities I would expect to see the different SmO2 values depending on day to day variation.

This is a link to protocols for lactate testing. There are also some articles on the site as well. Blood lactate testing protocols for cycling — High North Performance

Very similar main goal to me. Family history of heart disease though. I do a lot of riding below LT1, At least I thought I did until I got a lactate meter! I’ve be reduced the intensity of most of my solo rides as a result. Early days so I’ve yet to see any major effect of it. One thing though I know it’s not doing me any harm.

I did a lactate test yesterday, for the first time in about 18 months. I followed the protocol recommended by Alan Couzens in his Substack book—15-min easy warmup, then 5-minute steps of ~25w. For HR I just put a guesstimate of the average HR in the final minute of each step. For the final step, I did hit my HRmax of 183, and was surprised to see I was able to hold 180+ for the final two minutes of that step (I am 57). My BLa was 10mmol after that step, so I called it a day.

My main interests are:

  1. Seeing how BLa aligns with my RPE of LT1. I have been trying to keep my training really polarized, doing a lot of very easy endurance, so that I can add more volume. These days, I am doing a lot in the 190-205w range, which looks like less than 1mmol.
  2. Comparing these results to the two lactate tests I did near the start of training—off the couch in Dec 2021, and three months later in March 2022. These two tests were administered by others with different protocols (3-min instead of 5-min steps), so if anything, they were overstating my abilities back then.
    The three lactate traces are yellow for Dec 2021 (a true max effort, I still remember!… based on the ramp test I did, I would guess my VO2max was in the low to mid-30’s), green for March 2022 (they only tested to the first 1mmol rise in BLa, but I also did a metabolic cart VO2max test at the same time, with 47.1ml result), and light blue for yesterday.
    NB. The HR data is for yesterday only.
    Sorry if the chart is not formatted well—this is my first time to make a spreadsheet chart. Any feedback appreciated.
    ETA: Dec 23 is a typo. Read “Dec 21”


Tnx for sharing your data and congrats on improvements.



What would you mark as your LT1 zone? Around 210w?

So, my general idea with the test presented above was to just get an overall picture of my lactate profile. But I also wanted to get a better look at LT1, since the area below that is my primary training zone. HighNorth suggest doing a second test with 10min steps of just 10w for getting a better view of LT2, so I decided to apply this idea for drilling down on LT1.

So the day after the general LT test presented above (i.e., yesterday), I did a 10min warmup at 126w, then 5min at 158w, then starting at 186w, I did 10min steps, just bumping the wattage by ~10w each step. Aside from what seems like an aberrant reading at 195w, the BLa values stayed well under 1mmol all the way through 224w, so this entire range seems like it’s definitely below LT1. The next step, to 236w (a slightly larger 12w bump to keep the average at 10w), saw a rise to 1mmol, and from there it has a steady rise to 2.2mmol at the final 265w step.

Based on this, I would put LT1 for training purposes conservatively at 224w, where I had readings of 0.7mmol and 0.6mmol. In his Substack book, Couzens explains this interpretation of LT1 (AeT):

To account for the typical error in portable lactate testers, the magnitude of the initial rise is generally taken as somewhere between 0.3-0.5mmol/L. I recommend using the point before the first rise of >0.3mmol/L when defining the Aerobic Threshold. This was the number that the Sports Science team used at the A.I.S. and it works well for most monitors.

NB. The blue dots are the BLa readings from this test (10min steps, 10w increments). The green triangles are from the VO2max lab test I had done 18 months earlier, with 3min steps (VO2max tested at 47.1 for reference). The red triangles are HR.


Nice. Yesterday I also did some kind of testing like this. I had only 6 strips left so could no do a good test. Previous LT1 was around 215-220w.

Started at 155W, 180W, 195W, 210w, 220w,235W. And also tracked dfa a1 (what also for me gives good results). Lactate went up at 230W block so LT1 between 220-230W. And that is what dfa a1 also gave as result (LT1 230W).

So now get me some new strips and then do a better test. What do you guys do for warm-up? 20-30min? very slow and then ramp-up already. or stay very low for warm-up>?

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20-30 min constant at 55% MLSS


So thanks to my day job, I had an opportunity to perform a lactate test yesterday. I have no concerns about the integrity of the protocol (was very solid and facilitated by a trained technician), but I’m totally confused by the results and how to apply them to my training. The test vendor focuses on employee wellness and healthcare, not cycling performance. So their whole methodology is a bit apples to oranges.

Attaching a spreadsheet below that depicts my historical understanding of my 5 zones, based on accumulated experience.

Including the results from this test below. Unfortunately, the vendor doesn’t stick with the 5 zone model.

Is my understanding correct that my AeT(LT1) = 120bpm and my AnT(LT2) = 158bpm?

And if my understanding is on track – should I be doing more low and slow work in the 114-120bpm range? To date, I’ve been focusing on Z2 work in that 130-143bpm range based purely on the talk test.

Feel like I’m at the point I know juuuuuuuust enough to be dangerous here.