I did my usual 30 mins on the elliptical (including 5mins warm up and 5mins cooldown) and I noticed a big difference - I kept at the same level as usual, and my heart rate got up to about 75% tops when it's usually up to 85%. During my cooldown, my pulse dropped back down much quicker too.
I think this planned, rather than haphazard cardio and the MIIT must be working.