09/21/2026
Numbers DO lie… and here’s what doesn’t
On Saturday, I had a lactate threshold test that measures the point at which your body switches from burning fat as a fuel source (zones 1-2) to burning carbs as a fuel source (zones 3-6)
The reason it’s important to know this number is because it’s what helps you build your aerobic engine, which allows you to push higher efforts without fatiguing early
Building it is how I went from running a 6:21 mile to a 4:48 mile
However, over a month ago, I injured my Achilles running so I switched all of my cardio workouts to the bike
By my own estimate, I assumed my zone 2 was around a 123-134 bpm as compared to 133-142 bpm for running since it varies based on your activity
The lab this Saturday showed me that my zone 2 was at 83-95 bpm
So I biked at 95 bpm this morning for an hour, barely broke a sweat and didn’t even feel like I worked out
Even my Oura ring showed I was largely at zone 0-1 the whole time
There are a lot of factors that can skew the data such as the mask being too tight, which restricts breathing or even the muscular endurance in my legs giving out before my lungs do — artificially lowering my max heart rate to 149 bpm whereas I’ve seen it get as high as 182 bpm during my last HYROX a couple of weeks ago
Ironically, the most accurate way to measure if I’m actually in Zone 2 so that I can continue building my aerobic engine without running is through what’s known as an RPE Scale or my “rate of perceived exertion”
If I feel like I’m at a 4-5 / 10 effort, get into flow state and can peddle without it feeling too easy or too difficult, I’m in the sweet spot — usually around 123 bpm for me
This isn’t just unique to endurance training, numbers lie everywhere when it comes to fitness — the number on the scale, body fat %, caloric intake tracked, labs, etc.
What doesn’t lie is energy — your intuition about something and I have found that for this reason it’s equally important to pay attention to the qualitative data that the hard numbers simply cannot convey as to not get us off track by giving us a skewed data set
P.S.
Pricked the heck out of my index finger getting those blood samples (slide 4) 😂
