I’ve tried a variety of HR zone calculation methods.

First was 220 - age for Max HR, which yielded zones that seemed like overestimates of my heart’s work (lots of time in Z4-5).

The second was a calculation for Max HR from age specific to female athletes. The zones derived from this also seemed like overestimates.

The third try was a calculation via LTHR estimate from Joe Friel’s blog. This calculation has raised the bpm ranges, but I still wonder if it is overestimating cardio. My current inputs are an LTHR at 174, with a Max HR of 190.

I read in a forum that if you’re riding for hours in Z4, there must be an error in the zone calculation. I can go for (outdoor) rides which are predominantly in current Zone 4 range. For example, in a recent metric century: 2 hours in Z4, 30 mins in Z5, 1 hour in Z3, and 1 hour Z2-Z1. Unfortunately, I do not have a power meter, so I don’t have that data for my outdoor rides.

**Am I calculating HR Zones correctly?**

If this info helps: my Max HR during the ramp test was 185 bpm (steady, not a spike). My RHR is ~52. All-time highest recorded HR (since I’ve started tracking HR) is 189.