The lactate paradox results in lower lactate levels at exhaustion compared to sea level, potentially due to brain oxygen levels acting as a circuit breaker.

“there's something called the lactate paradox if you if you try and exercise to exhaustion at lower levels of altitude you actually give up when your lactate levels are lower than you would at sea level and so and and there's debate about what causes this and even whether it's a real thing but the the picture that that makes sense to me is is that it's these things are not just about how much oxygen is making it to the muscle it's also like what is that what is your brain oxygen level and so you're getting these other circuit breakers that are starting to come down that aren't even on this path from mouth to lungs to to blood to muscle there there's other factors that are saying whoa wait a second oxygen's getting a little low so we're gonna actually cut off the supply to the muscles or reduce it in order to make sure that we don't get stupid”