The indirect methodology for assessing mitochondrial function and metabolic flexibility using gas exchange has been validated against direct muscle biopsy methods with stable isotope tracers.

“in um in study that we we were going to be publishing soon we have validated this um um fat oxidation and carboh hydroxido condrive biopsis we inject um uh directly fatty acids pyate representative of carbohydrates right and glutamine representative of amino acids and then we can see that there's a very high correlation between this this indirect methodology to look at mandal function and the direct methodology which is through muscle biopsy and injecting the substrate and see how it's oxidized right”