This is really great info;
Do you think testing should occur in the same pattern as training as it relates to fasting?
Just wondering if LT1 is x during testing while fasted but all the training is not fasted the LT1 may be something different.
I have no idea but look forward to your opinion/advice/knowledge
thanks
my take on your question is thus: my personal lactate trends at around 2.2 mmol pre test with a few hours of not eating, then drops to about 0.6- 0.8 after 20 mins of light effort, before ramping up. but as exercise intensity increases, the liver releases glucose into the blood anyway. i’m not really fasted in testing (at 4 hours post lunch). i guess i’m thinking, don’t mess the test up with high blood glucose levels pre test, because you need to find your base reading, and excess blood glucose may alter the substrate used in producing ATP at low levels. once training intensity picks up the rate of glycogen use will typically be higher than glucose consumption, so its not a problem. again, in my case, i find testing lactate during long efforts at lt1 is not affected by carbs every 20 - 30 mins.
Hi Matt,
That is an interesting question and not one I had pondered previously. Am going to avoid typing too much speculation.
One could do an experiment:
A: Test for LT1 with a fasted protocol and long warm up to get an accurate number under those test conditions. Which is arguably a method designed to reduce variables but as you suggest, might not be perfect correlation to real world.
B: With a “good” fasted LT1 estimate in place, follow up with tests under the more “real world” conditions and see what happens. Will take more than one test because real world is not consistent.
What would one do with the data? For me, LT1 isn’t a specific wattage number that I try to train at with absolute precision. Rather, it guides a range (zone). I can watch it move up with fitness and I can feel the difference on the bike which are a couple ways of defining improvement. IF the numbers are close, I’d continue on. If the numbers are significantly different, would have to consider next steps.
Interesting question - thanks for adding it here.
-Darth
hi folks. back again. i did another lt1 test today, and had good predictable results until i got close to Lt1. i used 3 different fingers for the test, but went back to the same fingers a few times and got some odd results. the question i have is, does the wound from multiple prick sites on the same finger create a change in the measured lactate. does the healing process, or damage change the make up of the blood at that site to the point where lactate would drop sharply. i went from 1.7mmol to 0.5mmol, and repeated the test at 0.5mmol. i then went on with the test but had lost confidence. i used the same hygene protocol throughout.
i watched this tv show with dr podlogar, and have now learned that the liver converts fructose into glycogen, lactate, and fatty acids in differing %s. i did not realise that blood lactate would be raised in this way. i assumed that it only came from glucose oxidation in the muscle. perhaps this release explains why i typically have a lactate >2.5mmol pre test. after last nights red wine, ice cream, chocolate, and associated greed, my lactate is 4mmol at 8am. maybe blood lactate can be an indicator of fructose turnover in the liver. in this circumstance its not correlated with high hydrogen ions, giving a good reason why a diet, pre test is a factor in finding base levels.
Yes that’s the reason I believe you should be absolutely consistent in what and when you eat before a test together with how rested you are. Whilst giving you a great indication of training levels the test is more about establishing progress or lack of.
so the question i now have, is, does resting blood lactate level have an influence on fat oxidation. from sunday eves sugar and red wine binge, it took 24 hrs for my lactate to drop from 4.2mmol to 3.5mmol, to 2.0mmol, monday morn, eve, to tuesday morning. was my liver continuing to produce lactate to get rid of that excess fructose?
7). Don’t squeeze or massage to get a good drop. Get a bigger lancet.
My issue is getting enough blood, even with the 28g lancets. It seems like all the blood drains out of my arms and legs into the core!