Steady state cardio and HRM's

KBmoments

I've read plenty of threads about how using a HRM to calculate calories burned doing other than steady state cardio is not very accurate (HIIT, Lifting, etc). I do understand that and am not questioning it. My question is: What constitutes steady-state? What if I jog for 5 minutes, walk 1, jog 5 up to 45 minutes... is that considered steady state? Same with elliptical... or even hiking (b/c of elevation gains/drops). Or would I have to jog for 45 min straight OR walk 45 minutes straight to get the most accurate read? The first scenario, I would seem to burn more calories overall - in that case, would I just deduct less calories burned on my HRM because it might be inflated a little bit because of the "resting" calories being burned?