Zone 2

[Huntingnorseman]

There isn't substitute for doing a VO2 Max test to find your zones if you are serious about training. Most people I test have a Max HR within 5 BPM of their calculated Max HR and their zone 2 is lower than the Max HR based formulas show. With a VO2 max test done a machine with a CO2 sensor the maximum aerobic HR is very clear. In most people you will also see clear metabolic changes at the zone 3, zone 4, and zone 5 transitions.
The most accurate formula based calculation I have found is MAF (Maximum Aerobic Function) if you are honest with yourself and use adjustments. https://philmaffetone.com/method/process/

 

[Cuz]

There isn't substitute for doing a VO2 Max test to find your zones if you are serious about training. Most people I test have a Max HR within 5 BPM of their calculated Max HR and their zone 2 is lower than the Max HR based formulas show. With a VO2 max test done a machine with a CO2 sensor the maximum aerobic HR is very clear. In most people you will also see clear metabolic changes at the zone 3, zone 4, and zone 5 transitions.
The most accurate formula based calculation I have found is MAF (Maximum Aerobic Function) if you are honest with yourself and use adjustments. https://philmaffetone.com/method/process/

Ok, so, using that MAF formula, I get an AeT = 123
I "think" that sets my Z2 between 110-123.
I'm not sure how to calculate the rest of my zones from here.

Using a Max HR test on a rowing machine, I get 178 as my MHR.
That sets my Z2 between 106-124.

There doesn't seem to be that much difference. Am I missing something?

 

[V2Pnutrition]

Am I missing something?

Not at all. Which takes me back to my first post: if you use how you feel as a gauge, you're going to be pretty dang close to the sweet spot. Admittedly, it'll take a bit to get an idea of what this "feels" like. I've found most folks fear that they're not going hard enough for it to be doing anything.

The watch and HR data can be nice to use a tool for comparison during this time. That said, don't let drifting into the high Z1 or low Z3 force your hand to slow down or speed up. You'll know if you're not at a pace you can sustain for a prolonged period of time or not. Use the HR to develop a relationship in your own mind between what your effort feels like and a given HR.

As others have said: the accuracy will go up significantly with a chest strap vs wrist-based monitor.