Hi everyone. Curious if anyone here is doing field testing with lactate during their rides?
I’ve been digging into the data recently and I’m wondering if anyone has tried correlating spot-check lactate numbers with live data from a CGM or hydration sensor?
I know it’s a bit of a dark art, but I’m trying to dial in my optimal zones. Specifically, seeing how fueling strategies (glucose trends) might be impacting lactate accumulation. Is anyone seeing actionable patterns there, or is it just too much noise?
Would there be any correlation? It seems to me that the lactate would be largely a result of the work you are doing (whether fueled or not) and glucose would be largely a result of fueling (whether doing any work or not).
Lactate is processed into glucose via gluconeogenesis. However, as a T1D who actually has a use for a CGM and is therefore on one 24/7, I typically see the glucose increase as a delayed response, sometimes well after an interval is completed. This would come down to how well your body clears lactate. I see a blood glucose spike because my body doesn’t make insulin to lower it—I have to react after it starts to rise. I don’t know how quickly a non-diabetic’s body would react or what the bg curve would look like.
I see this as akin to “no one should ever buy a $12k bike”—if you’re good enough to leverage it properly, you’re a pro who is being given it. Likewise, if you need to know your lactate levels live via interstitial measurements, you’ve likely got someone taking care of lactate tests rather than trying to map it to glucose levels. If not, it’s overkill. Just do an ftp test, calculate your levels, and you’re close enough for 99% of athletes.
Oh, and CGMs are not even a live reading of your blood glucose levels. They’re an algorithmic guess based on interstitial glucose levels that doesn’t handle spikes very well, making them even less effective for this use case.