Zone 2 testing with lactate production is a functional test that measures the body's ability to generate ATP via oxidative phosphorylation under increasing demand.

“looking at how much output can you generate while keeping lactate in this sort of 1.7 to 1.8 millimolar range and certainly once you're over 2 you're starting to escape the capacity that mitochondria a little bit”

“It's sort of like in a magic scenario, in a magic world, You would have these data on every single person. You would want to know what is your zone two threshold. And that becomes a way to assess mitochondrial function.”

“If you produce a lot of lactate, that means that you don't have a good mitochondrial function either because lactate is metabolized in the mitochondria. So if it's in the blood, that means that the mitochondria cannot metabolize it.”

“If you burn very little fat... that means that you don't have a good mitochondrial function and that confirms it, that test.”

“but it's important to understand that a functional test is a very important test in medicine we don't have many functional tests right most of the things we talk about are biomarkers um and by themselves they don't tell you a huge amount of information they tend to be quite static and not Dynamic but we understand that the healthier individual is the more they can rely on their mitochondria for ATP generation under increasing demands of the cell”