I know its superhuman

If they start selling that in pill form, I hope she gets hella royalties.

It’s not a problem. It’s adaptation. The human body is incredible, though different people will have different levels of ability so adapt to different stimuli. Thats why some people become olympians and some miss out despite training, eating, and sleeping in the same group.

Lactate buildup is acute, and not likely a factor in the ability to perform repeating ultramarathons.