Is Lactate a Causer of Fatigue?

Lactate is actually not a causer of fatigue. It's guilty by association rather than actually being guilty because it's also present. Lactate can be redistributed back to the liver and converted into glucose. So you're actually using lactate as glucose or your heart can use lactate as lactate. But ever since he told me that, it's blown me away. People still talk about lactic acid. Is that a thing really? Is that just some bullshit people talk about? I think it makes sense that this stuff is produced in a state of fatigue because it's just kind of think about it.