First lactate test - what went wrong?

Training
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Hi all,

I ran a lactate threshold test today (FTP = 259 W) with:

20 min warm-up

6 min stages at 10% FTP increments

Samples at end of each stage (2nd drop, alcohol cleaned, dried, assistant helping)

Everything looked good until 70–80% FTP (~181–207 W). At 60% I had 1.6 mmol/L, but at 70% it dropped to 0.8 mmol/L. and at 80% to 1.2 mmol/L. I repeated the measure and still got that low value. Afterward, the curve rose normally again (90% = 3.1, 100% = 5.7).

Questions:

  1. Is this likely just bad sampling/device error, or can lactate really dip like that?

  2. Would you smooth over it and call LT1 ~180 W and LT2 ~260 W? Or how to create zones now?

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2

Id look at that differently and say it wasnt going good until 70%

I would say your 70%+ looks about right from a typical lactate curve & that the 30-60% area is wrong.

2 Likes
3

What device did you use?

Once lactate starts to rise, it doesnt go back down. the 0.8 maybe is suspect measurement too.

I’ve gotten several tests like that. Samples tend to get noisy in that z3 range. Probably because of contamination. Best to take a second sample if you think one is suspect. Also, easier to just stop pedaling to get a clean sample.

I had an edge first, that one always gave me issues in that range. Meters with shorter turn around times are much more consistent, especially if need to take a second sample.

Did you test lactate at rest? Easier to see if warm up is long enough if you take baseline. You also might want to start at 75-80W next time.

6

Lactate Plus, did a 20min warmup at 40%. First measurements is before the start. The funny thing is that I did 2 measurements and those weird levels and they both came the same, and I was careful to clean with alcohol first, and then take the 2nd drop every time.

7

Hard to believe, I’m pretty sure I’m well over z2 after 200w, based on experience and how it feels.

8

If you scrap the 180w point, the curve looks much more normal.

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9

The 180W point could have been contaminated. Did you take that twice?

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10

Not that one but for me 1.2 at 225 watts is way more abnormal since I know I’m out of zone 2 at that point.

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11

Agreed.

Also, what was the purpose of the lactate test in the first place?

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12

To get better insights into my potential zones for training

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13

It’s been common for me to get results like you have. Usually one or two points that look out if whack.

How do you define zone 2? FTP?

you started at fairly low lactate and got a .5 jump up to .8 after a few steps. While low on absolute scale, that is a bigger size step change. Did you have a lot of fluids before? Blood concentration could influence the test.

i’d recommend a little longer warm-up. Starting a little bit lower wattage. Once you get a big jump in first half or so of test, double check the sample.

Lactate testing is harder than it sounds to get good data and interpret.

16

IMHO a single test is not useful, you need to build your baseline first. That’s because rules-of-thumb like lactate level at FTP = 4 mmol/l are averages and you have quite a bit of variation amongst people.

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