Lactate is used as a fuel - by everyone. It's all actually really interesting: TCA cycle (a.k.a Krebs cycle) in the muscle https://en.wikipedia.org/wiki/Citric_

Lactate is used as a fuel - by everyone. It's all actually really interesting: TCA cycle (a.k.a Krebs cycle) in the muscle https://en.wikipedia.org/wiki/Citric_acid_cycle https://en.wikipedia.org/wiki/Citric_acid_cycle and kind of also Cory cycle (which involves the liver) https://en.wikipedia.org/wiki/Cori_cycle https://en.wikipedia.org/wiki/Cori_cycle