The Definition of EPOC
I found Suuntos definition of EPOC. It stands for “…Excess Post-exercise Oxygen Consumption and indicates the amount of extra oxygen that your body needs to recover after exercise.” and “…the higher the EPOC, the more demanding the exercise…”, so it does sound a little like TRIMPS, except that I don’t understand how they can measure Post-exercise Oxygen Consumption while you’re exercising. I could understand if you were supposed to wear the heartrate monitor for an hour or two after exercise, but you’re not.
So I’m a little sceptical, Suunto can at best measure the stimulus that results in EPOC, but they’re certainly not measuring it directly.
There’s a Wikipedia article about EPOC too.