Lactate and the Krebs Cycle

Lactate is indeed not an acid and it's not actually what's causing uh your muscles to burn there no not a bit. lactate gets used as a fuel also so like really where does it go you know to what degree does it get taken up by working muscles and other tissues? It was actually thought to be a dead and waste product up until about the 70s but now that we know that lactate is not a dead end waste product, why do we have workouts like quote-unquote lactate tolerance workouts?"