I've been trying to get more exercise and, short attention span and lack of time that I generally have, I've been doing some HIIT workouts such as the 7-minute workout. I know that the "7-minute workout" is really intended to be repeated 2-3 times in a row. However, I also know that I can generally barely manage to get through the 7 minutes with my current level of effort, with my legs being rubbery enough at the end that it's a relief to end with planks.
So, my question is, if I'm aiming to do 3 sessions worth, should I push myself hard and resign myself to the fact that, at least at first, those second and third sessions will involve me slowing down as my endurance wears do, or should I be pacing myself so that I'm exhausted at the end of the 3, but I'm keeping a consistent level of effort?