Confusing Lactate Meter Results

  • Creator
    Topic
  • #38149
    mjb
    Participant

    I finally committed the $$ and bought a lactate meter.
    I went for a run this morning and got a few results that were confusing, I’ll do another test again soon, but feel there is a potentially valuable question in here regardless.

    My plan was to take blood lactate levels before and after a 60min Z2 run.

    Results were:
    – 0.9 mMol @ 5:05am (pre run. Run was from 5:07 – 6:09am)
    – 5.2 mMol @ 6:11am (2 mins after end of run, way higher than reasonable given the slow pace, after the test I noticed the strip was touching the zip on the carry case for the meter, so I feel comfortable ignoring this result)
    – 1.8 mMol @ 6:13am (4 mins after end of run, I washed my hands before this test, just incase that was part of the problem. This was almost exactly the result I would have expected, but being a numbers guy, thought I’d follow up just to be sure)
    – 0.7 mMol @ 6:15am (6 mins after end of run, no idea why this number would be invalid, but I don’t think it’s likely that I managed to metabolise that much lactate in 2 mins)
    – 0.9 mMol @ 6:17am (8 mins after end of run, the fact this aligns with the previous test is a bit odd).

    I suppose the questions arising from these results are:
    – how quickly does the body potentially metabolise low levels (aerobic levels) of lactate after exercise has finished?
    – how often does the Lactate Plus give wrong answers compared to error messages?
    – how many people buy the control solutions with their meter? I didn’t, but am now thinking perhaps I should have done.

  • Participant
    Michaeltyoung on #38161

    I recently got one as well. I’ll share some insights mostly gained from a close reading of Scott’s guide here on UA as well as the triathalon guide on lacate.com (it’s hidden under site map).

    For aerobic runs you should be messuring lactate levels *during* the run. if this isn’t feasible then measure immediately after stopping. Even 2 minutes is too long. Taking multiple measurements post-run is more meaningful for speeds which involve substantial anaerobic metabolism (maximum lactacte steady state and above) since at that intensity lactacte should actually continue to increase after you stop as lactate leaks out of your muscle cells. But if your lactacte increases much post-aerobic run you might be working too hard since the lactate produced during aerobic work should be below your shuttling capacity even while stopped.

    Think about what purpose is in using the meter. For aerobic efforts the goal should be to pin down your aet or verify you’re below your aet.
    For z3/anarobic threshold efforts the goal is to find your maximum lactacte steady state which should correspond to your anaerobic pace. According to lactate.com, incresses in MLSS speed directly predict changes in race performance (although i wonder whether they were really thinking of ultra/all day efforts when they said that). For efforts above your anaerobic threshold the goal is measure your anaerobic metabolism ( probably not useful unless you’re training for a track event)

    Consider doing a step test to measure your speed/hr at aet (1.8-2 mM or 1mM above baseline) and optionally your speed/hr at 4mM. There’s nothing special about 4mM–this may be above or below MLSS, but it approximates efforts that mix aerobic and anaerobic metabism and changes in speed at 4mm is supposedly a good benchmark for changes in fitness (but so are changes in speed at aet, especially for longer events).

    A couple of thing’s I’ve learned:
    Use an alcohol wipe and dont subsequently touch your clothing with that finger.
    Wipe away the first drop of bloods on a clean paper towel.
    You want a nice spherical blob of blood. And the more blood the more likely the reading will be accurate. It’s good if there’s blood left over after you fill the reservoir on the strip. I think this is because contaminants get diluted. If there’s not a lot of blood, you’ll need to lance a second time or else risk wasting a strip on a questionable result.
    If you’re resting solo, single use lancets are convenient. Be sure to get something that goes deep and wide for lots of blood. I use 1.8 mm depth with a 23g needle. That may be excessive if you’re not a climber.
    If you’re on a treadmill you can prep the reading (alcohol, strip, lancet) while running. You really only need to step off to touch the blood to the strip.

    Finally, it took me a couple of vials to start getting (mostly) consistently good measurements so be stick with it.

    Keymaster
    Scott Semple on #38193

    What @michaeltyoung said!

    @mjb: I think you’re safe in assuming the 5.2 reading was contaminated.

    Participant
    mjb on #38538

    Thanks for the response @michaeltyoung
    There’s some great info there.

    I was trying to test straight after my run thinking that it would be a good check to ensure I was in Z2 before I make the time to do the proper treadmill test (need access to a treadmill). But if the results are likely to be that sensitive to a slight delay, maybe thats not going to be a useful practice.

    I’m looking forward to finding a treadmill and partner to help do the proper test protocol. My current AeT is based on the TrainingPeaks HRV method and was done a while ago (my TP expired and I wasn’t feeling the value of renewing).

    Participant
    Dane on #38549

    Just to add to the contamination point, there’s a lot of lactate in sweat (up to 10x the concentration in blood) so you have to really make sure the blood drop isn’t getting contaminated which is difficult by yourself when you’re working hard.

    The best practice I’ve found is pretty much what others have said: use a clean paper towel to wipe all the sweat off the finger I’m using, puncture the skin with the lancet, push out a drop, wipe it off again really well with the paper towel, and then push out another good sized drop of blood, find some way to keep my hands steady (resting them on a stable surface helps a bunch), and make sure to only touch the very top of it with the strip and let the capillary action draw it into the measuring chamber on the strip. If you push the drop of blood out and it gets watery and runs out over your skin (ie it’s not a nice, raised, freestanding drop) it’s probably going to give you an error or falsely elevated result. In that case I either wipe off my finger and try again or find a new site.

    The cool part of sweat containing lactate is that there are companies working on skin sensors to measure lactate (along with a bunch of other biomarkers) so maybe sometime in the future we can just glue a sensor to our skin that measures the changes in lactate concentration while we exercise instead of dealing with capillary blood.

    Keymaster
    Scott Semple on #38641

    The cool part of sweat containing lactate is that there are companies working on skin sensors to measure lactate (along with a bunch of other biomarkers) so maybe sometime in the future we can just glue a sensor to our skin that measures the changes in lactate concentration while we exercise instead of dealing with capillary blood.

    That would be fantastic.


    @michaelbarnes
    : I do solo AeT tests all the time. You don’t need a partner if you’re organized with each sample and test at the same interval after you step off the treadmill. I’ve tried 30 and 60 seconds after and didn’t notice much of a difference.

    I can’t remember where I read it, but the recommendation I recall was 60″ after stepping off. There’s a delay between lactate in the muscle and that same lactate appearing in the blood. So even if you could sample immediately after stepping off, you wouldn’t be measuring your output at that moment. The sample will reflect the effort at some amount of seconds before.

    I suspect 60 seconds was the recommendation from either Olbrecht’s book or http://www.lactate.com. I haven’t been able to track it down.

    Anyway, 60 seconds is pretty manageable; 30 seconds is more tricky.

Viewing 5 replies - 1 through 5 (of 5 total)
  • You must be logged in to reply to this topic.