bellissima, what do the zones actually mean?

It seems to me, as I said before, that my old old Garmin derived mine reasonably accurately, at least as they correspond to my perceived exertion.

My MHR for running is around 188, resting around 50, but it goes up pretty quickly with any activity. Zone 1 starts at 86 according to the Garmin, which is about where it goes at moderately brisk walking. But then Zone 2 doesn't start until 146, which is about where my respiration rate starts to increase appreciably. I can't run at all, not even a slow jog, with a HR below around 135, and if I can keep it there, I do NOT feel like I'm working.

So from there, zones 2 through 5 are quite narrow - 9 or 10 bpm. That doesn't make a lot of sense, and it's tough when I'm supposed to stay in zone 3, for instance ... but again, it works with my perceived exertion.

What's your take???