I didn’t do a test yet. I’m just getting started and don’t have access to a treadmill right now (like a lot of us, I assume). I used the MAF formula to get an idea. I’m 36, so 180-36=144. I took an extra 5 off since I haven’t been training. That puts me at 139. My heart rate was up in the mid 140s pretty quickly, and I don’t think I could have slowed anymore without walking.
I’ve also had an idea in my mind that it’s supposed to feel easy. This is the first time I’ve ever tried to go easy instead of running hard and killing myself. Since my runs haven’t felt easy and I was breathing really hard, I assumed I had moved up into a zone where I didn’t want to be.