It has been a few years so maybe the technology has improved. My cardiologist explained that the Garmin technology only gets that level of accuracy if their calculation of max heart is accurate. With my conditions, he felt that my max heart rate calculation would be off by far enough to make it next to impossible to optimize based off of that data.

I'm in significantly better shape now. The next time I see him, I'll ask about VO2 max again - it's the only metric that my metric obsessed triathlon/running friends talk about that I don't have a timeline for.

Now all I need are wrists big enough to wear an actual adult sized watch.