Peter Attia's Zone 2 power on a bike has increased from approximately 170-175 watts to 215-220 watts over a few years, with an aspiration to reach 240 watts.

“I have checked my lactate level after every z2 workout (4 per week) for about 4 years now on cards like this.”

“finished a long zone 2 ride with frequent lactate sampling, then 5x5 hex bar deadlifts”

“my zone two heart rate has also gone up over time with my zone two power so as i've gotten more efficient i can not only do more work at zone two but i can actually sustain a higher heart rate at zone two although as far as i can tell my maximum heart rate has not changed one iota in five years”

“if i can train 12 to 14 hours a week i want it to be very specific and if i'm gonna take time off it's gonna be playing with my kids which maybe that's zone one but i'm certainly not gonna sit on a treadmill or a bike and go you know at 150 watts like i'm not gonna do that now because i just have a better use of my time whereas i did that kind of stuff when i was spending 28 hours a week on a bike which i was at one point in my life”

“when i did my first zone two test it was about 175 watts uh maybe 170 watts on a bike and i was shocked i was like that's really amazing that it could be that low given what i know it used to be and you know today it's about 215 to 220 watts so that's better and i think my aspiration is i want to be at about 240 watts by next year”

“i check my lactate after every single zone two ride and since i'm doing four of them a week and i've been doing them for almost three years and i write down every single day i write down this was my power this was my heart rate this was my lactate”

“so i do zone two about four times per week and each time i do it i actually use a lactate meter just to make sure i'm right on that limit of not going too far not pushing too hard but pushing hard enough so i'm almost always doing it on a bike a stationary bike that's hooked up to a power meter and i'm titrating my watts and my heart rate to get to a point where my finger stick lactate level is 1.8 or 1.9 millimole”

“what I do spend is about three hours a week in zone two and and again there's so many different ways to describe zones so I'm not doing this in terms of heart rate I'm really defining this in terms of mitochondria so Zone 2 is my highest work my highest power output where my lactate stays below 2 m”