Just my experience. I rejoined the gym in April, and did a few sessions with a trainer as there was an offer on. Now he bases his training around HIIT ( High Intensity Interval Training) and looks at diet/Insulin which is what caught my attention. In the sessions we did virtually no cardio work and focused on free weights (although this does work the heart too). The sessions were fun and he pushed me to a place I didn't want to go, but really needed to. Sure I ached for a few days, but I expected that and I didn't die.
Anyway, since those sessions, and now going to the gym 3 times a week and doing mostly weights, I'm seeing 6's on the meter regularly. Yes, it does rise initially but it soon drops again, and the effect seems to last a few days. The one piece of cardio kit I never thought I'd like and yet do is the rower - it gives a good overall workout and doesn't seem as tedious as bikes or running machines to me. Sometimes I do 5 minutes as a warm up before the weights. Sadly, my diet has slipped in the last 2 weeks so I need to nail that again.