Trying to keep my HR in the moderate zone is difficult
I'm 43 y.o, 6'4" and 235 lbs. Long story short I've been trying to switch up my workouts from HIIT (I also do HIIT style when weightlifting) and treadmill incline walks which target vigorous and peak HR zones to exercising where I keep it in the moderate zone. From research this will target more fat burn as high intensity takes from glycogen storage. I'm trying to target more abdominal fat but otherwise I'm just trying to maintain. Also, I've been trying to get my RHR down and sleep better. I think the high intensity has had an effect on those things, especially since I do them often.
But trying to keep my HR in the moderate zone is more difficult than doing high intensity workouts lol. Weight lifting is impossible to not spike up into the vigorous zone, treadmill I feel like I'm doing nothing with the incline at 8 and speed at 2, and I try to modify the HIIT exercises to slow it down and take longer breaks but 10 seconds in I'm already hitting the vigorous zone. I know walking is good but I'm in Texas and it's too damn hot for that. My HIIT workouts are bodyweight at home.
Any ideas on what to do? I just tried a HIIT workout at home and what usually takes 30 mins, took me an hour because I had to wait until my heart rate went down. I feel lazy trying to keep it in the moderate zone.
For context, I have a pixel watch and I have it set to vibrate when my zone changes and it sets your zones off my personal heart rate history, sleep, RHR etc. My moderate is 115-134.