Next time I will take resting heart rate, midway through the cycles and again at ending. Shouldn't be hard since we have a pulse ox in our aid bag.
After all said and done I am legitimately wore out. Feels good because I haven't been pushing the cardio as hard as I could simply due to boredom of the treadmill.
Can see this will be a big help in keeping cardio fun and short (25 +\- minutes) yet taxing enough to reach target heart rate and beyond.