Wednesday: 4×20’/1′ rest – lactate test at 175W

This morning I had a meeting with a customer so, I was unable to get out on the water. Pity, because it was a beautiful, cool, sunny, windless day. But I was able to make time for an erg session in the early afternoon.

I decided that today would be a good day to run the next installment of my lactate level during endurance session experiment. Last time, I was running at 180W and my HR and lactates blew through the roof! Today, the plan was to back off the power to 170W and measure lactates every 20 minutes during an 80 4×20’/1′ rest session.

Here is the plots for watts, SPM and HR. As it appears, it was incredibly easy. My HR nudged into the UT2 zone, and only by a beat or two and only in the last 25 minutes or so. I tried to do 170W, but it I was in a groove in the first piece at 173W, and then, after that, I just decided to hold 175W. My HR was so ridiculously low, I didn’t see much harm.

Screen Shot 2015-09-23 at 4.57.48 PM Screen Shot 2015-09-23 at 4.57.28 PM

Workout Summary – Sep 23, 2015
–_|_19047_|_80:00.0_|_02:06.0_|_175.0_|_17.8_|_128.1_|_ 59.7% _|_13.4_|_09.8
Workout Details

01_|_04745_|_20:00.0_|_02:06.5_|_173.1_|_17.8_|_120.3_|_ 54.1% _|_13.3_|_09.7
02_|_04766_|_20:00.0_|_02:05.9_|_175.5_|_17.6_|_125.8_|_ 58.0% _|_13.5_|_10.0
03_|_04766_|_20:00.0_|_02:05.9_|_175.4_|_17.9_|_132.1_|_ 62.5% _|_13.3_|_09.8
04_|_04771_|_20:00.0_|_02:05.8_|_175.9_|_17.8_|_134.2_|_ 64.0% _|_13.4_|_09.9

When you compare these results to the last two tests, it becomes clear just how sharp the between training at an intensity below the aerobic threshold and above it. At 181W, I was producing just a little bit more lactate than I could process and the levels steadily climbed. At 176W, I was able to process all the lactate produced and the levels stayed low and actually declined after 40 minutes.

The other thing that is clear from these results is that when my lactate levels are stable, the amount of HR increase is lower than if I am accumulating lactate, but the effect is not that pronounced. A big difference is the HR after 20 minutes.  And then the rise from 20 minutes to 80 minutes was 13% or 21% for the higher wattages and 10% for the 175W.

lactate table

But, I think this illustrates that the best way to train at or below 2.0 mmol/l lactate level is to actually measure lactates.  At best, there will be a short term, loose correlation between HR and lactate, and one of the primary effects of endurance training will be to increase the HR at which you are not accumulating lactate.

Here the plot comparing HR and Lactate for the 3 trials.

3 lactate tests

Pretty remarked the difference 6 watts makes!  Now, I just need to slowly inch up the power and keep testing at 20 minute intervals to make sure I stay at or below 2.0mmol/l.

Now I am on a plane to California.  I plan to do an easy endurance session tomorrow morning (HR cap of 70% HRR, 145).  And then take a rest day on Friday since I have an early flight and don’t arrive home until evening.

14 thoughts on “Wednesday: 4×20’/1′ rest – lactate test at 175W

  1. Richard says:

    Shares at have gone up on this news, ha ha just kidding.

    Testing every 20 to get a good picture is the best way to do it. Eventually an after 20 mins and end of row reading may suffice. But then there is that not knowing what happened in the middle that will bug you 😉

    Will someone please invent an accurate really time non invasive lactate meter already. We can send man to the moon but not this! BSX have brought out the next gen of their device (1st not getting great reviews) giving real time muscle oxygenation which has a correlation to lactate but still not proven exactly how to tie the two together. So almost there maybe?!

    Great to see you backing off and getting a true whole 80mins below 2.0mmol. The dip at the end is really interesting to see as well. I normally only do 3×20 so will be interesting to see if I get the same.

    Coming off of the water on to an erg, I have found I also have to dial back my watts. It is strange that it feels too easy also I worry because it gets to the point where the work is almost too easy that I can really shut off my breathing, I try to combat this by concentrating on big breathes.

    I think knowing your end lactate is as / if not more important as knowing it after 20 mins. When I asked McChase about this last year there was almost a set in stone assumption that lactate would go down from the reading after 20mins, as you have proven this is not the case (at least in rower that are not juniors). My and a lot of other results show this as well.

    Thanks for sharing Greg.


  2. Richard says:

    Oh yeh adding to this I always seemed to have a shitty day where my lactate was nice and low after 20mins and with same pace as normal would increase. Always a Thursday Morning for some reason. Knowing information like this can help to adapt the training for days like that.


    • gregsmith01748 says:

      Yes, that’s the meter I am using. The cost of the strips is the biggest problem. The meter itself seems like a reasonable price. You could probably find a few people in your club that would even split the cost with you. It’s definitely a good thing to share with other folks, especially if you can erg in a common place most of the time.


      • gregsmith01748 says:

        I’m sampling a lot right now because I’m trying to understand and get a full picture of where my aerobic fitness is now. If the first test had yielded expected results (readings around 2.0 or a little higher), I would have gone back to testing just at 20′ and probably not every session.

        But seeing how high my lactates got, and seeing the linear rise at a low power was really confusing and unexpected. The literature seemed to indicate that a plateau should occur for an intensity below your lactate threshold, which is about 4.0. Also, that you would reach that threshold more quickly, like within the first 20 minutes. Since my results were weird, it got me intrigued enough to do more extensive (expensive) testing.

        I think you have two advantages over me. First, I think you have a much longer history as an endurance athlete, so, your aerobic base is more durable than mine. Second, I think you have a better sense of intensity in your training than I do. I think I habitually push steady state training too hard, and that has eroded my aerobic base. So, I bet lactate testing for you would probably yield fewer surprises.

        Liked by 1 person

  3. Richard says:

    Sander, I have had issues with the cost of the lactate products as they are all but the same as Glucose devices. The difference is the enzymes used to detect the concentration in blood. Some Glucose devices are below £15 (20EURO) and strips really cheap. Lactate devices aren’t obviously used by millions of people like the glucose devices for diabetics. But surely the glucose market should have subsidized the lactate meters in some way!

    News on this to follow if I hear back from a company I have been trying to get some from for a while. Only had a unit to test which works really well. I may have found a low cost solution £120 GBP including 50 test strips, with top of the market accuracy quoted as good as Lactate Pro 2 with fast read speed 10 seconds. I will PM you on one of the forums if I get more info. If I don’t hear back from the company in the next 4 weeks, I will give you my source so you can get your own.

    I think when the retail price drops lactate will be used by individual athletes a lot more. Problem is most of the distributors/retailers deal with organisations (Vets, Health Services, Sports Labs) who will make a lot from the devices and so can charge a premium for the device.

    Liked by 1 person

  4. stelph82 says:

    Great post Greg and exactly inline with my own findings. Like you say, the general trend for HR when I am training at too high a wattage is that it increases over time, however when I am at the correct lactate level (or just below) it tends to level out after the first 20mins or so and only increase very slowly if at all.

    I found that doing two tests per long erg is the best, one after 20mins and another at the end of the erg to check for a rise in lactate, that way I can check if the lactate has risen over the whole session but I am saving 2 strips than if I was testing after every 20mins


  5. Boris says:

    Greg, “training at an intensity below the aerobic threshold and above it” is NOT at “below 2.0mmol”.

    BELOW aerobic threshold (AeT) is usually more at 0.6-0.9mmol, but this depends on the athletes “background”. Determining AeT is best done by spiroergometry. The findings from there can be then “coupled” to the personal lactate baseline.


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