Peter Attia· MD
the key is how much energy do you have to put into maintaining a sustained dose and that's the biggest challenge bob with zone two is you don't want it to be vacillating and that's why ultimately i love being on an erg mode of a bike which is i don't actually have to think about it it's putting 200 watts to my wheel no matter what i do even if i slow down or speed up it's just always keeping the watts the same