Lactate Test Help

Hi, just completed a lactate test to compliment the INSCYD test I did with Ryan a week ago.
I am having some trouble interpreting the results though, and was hoping for some guidance.

Test was done at 0615 fasted.
Lactate Scout 4
Lactate was taken at rest prior to starting HR 70, La <0.5

Hopefully my upload worked and you can see my results, I stepped up in 25 watt increments all with 6 minute steps except for the first one at 100W which was a 15 minute warm up step.

The main issue I am having is that Resting, 100,125 and 150W all came up as <0.5 (tabulated as 0.5 on the graph) does this sound right?

Any advice on where my LT1 and LT2 are would be great, or on how I could improve the procedure.


Were you fasted for your Insycd Test?

No, I ate before and during the inscyd test

I would highly recommend repeating the lactate test - fuelled the same as you were for Inscyd.

If you were fasted these lactates will be lower than normal, and therefore give smaller deflections.

If you can repeat the test in a normal fed state I would be happy to help on the forum.

If you when you do that test you can send me the fit file that goes along with the lactate test I can use my own software to graph this.

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Will do. Appreciate the input.

LT 1 is usually defined as the point where you cross 1 mmol: between 175 and 200 watts in your case.

LT 2 is usually defined as the point where you cross 4 mmol: between 225 and 250 watts in your case.

The main issue I am having is that Resting, 100,125 and 150W all came up as <0.5 (tabulated as 0.5 on the graph) does this sound right?

That can be right. It is the power you can produce with type I (and IIA) fibers (oxidative, no glycolisis, no lactate)

This is my new lactate test when fueling. The standard LT 1 and LT 2 seems to fall within similar ranges to my previous test but those early stages now follow a more expected curve.
Steve I will send you that fit file.

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Thanks if you can send the first file as well.

Thanks for the reply. May I ask where you get 1 mmol from and why? I ask because I’ve also heard 2 mmol or 1 mmol above your lowest lactate reading.

1 or 2 can be debated, but it is about the physiology: as soon as the lctate production increases, you have reached a different training zone

Okay. That definitely seems a logical way of putting it.
Why do we base LT2 off 4 mmol then? Would purely going off inflections in the curve be more appropriate?

I just find it a bit confusing as to what marker is the most appropriate.
I feel if it’s to help set training zones then the inflections are probably better but if it is to monitor progress using hard points such as 1 and 4 or 2 and 4 may be better. Does this sound reasonable or have I got it all wrong?

Inflections points are the only good answer indeed. 1/2 and 4 are just averages.
(where 4 is the point where you cannot maintain a stable level of lactate).

And I’m guessing the gold standard is to do a proper MLSS test based off the inflection point.

@Hank_Reckless, Question back to you: What marker is meaningful to you to guide your training decisions now that you’ve generated your lactate curve?

You can gain valuable information from nearly every point on that curve. The questions are, what do you want to pull from the curve, what does that data mean to you and your next steps, can you track progress with that data?

If you say that you want to track power @4mmol, run with that. Whatever you’re using to identify those transition points, try to maintain consistency from test to test. E.g., don’t use 4mmol for one test and then Dmax for another.

@ryan I hadn’t heard of Dmax so had to do a quick read up on it and applied it to my lactate curve, it coincidently seems to align with 4 mmol anyway (this time).

To answer your question though, I think the most meaningful marker is that which actually represents changes in physiology as @kjeldbontenbal suggested. the fixed mmol markers would make it easier to track changes in the curve but they may not actually represent anything.

The information I find meaningful is anything that is going to drive my training in the right direction, its the whole reason I did the INSCYD test with you and also decided to purchase a lactate monitor. To take a stab in the dark at what my actual physiological training zones are when there is an easy (though somewhat costly) fix for it would be a disservice to the amount of time I invest into training.

Hello @Hank_Reckless sorry this took a few days.

In the second test I see good data, nice deflection and 2 clear points.

I don’t believe in using absolute numbers for lactate . I use this first onset deflection as an endurance ceiling, send deflection as threshold. A good test will show these two.

Your first test fasted shows different deflection (and because we know less lactate production in this state, means there isn’t much to deflect)

I had a consult the other day, the person told me they were told by someone that endurance, below LT1 will result in lactate between 1.4 and 2. They did 1 hour at their tested LT1 - over the hour the lactate went from 1.1 to 2.3 - so more than one mmol - clearly not steady state that we woudl expect from endurance at this pace, also this increase would actually be someone else’s definition of maximal lactate steady state???

So I like deflections, I use them as ceilings for my zones.

All the best with your training!

Eat the same every time you do a lactate test and try to be in a similar training state.

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@steveneal thank you very much for graphing that up and for the reply.
Just to clarify something… if my first test fasted showed deflection at 150W and second test fueled showed deflection at 175W, should I be using them as my respective ceilings when training fasted/fueled?

Hi, you are welcome.

I don’t do fasted training with my athletes so I don’t have any data to back that up.

It would make sense though if you find a trend with your body over multiple tests fed and fasted, and your power is always lower might make sense.

Alright I’ll keep an eye on it and see what I find.