Okay, if you don't have one. You got to get one!! A heart rate monitor that is.
So far Zumba has burnt the most calories. As for Spinning, no guessing which class April gave - that would be the one with the most calories burnt for Spinning. That was an amazing class and I hope to be able to sneak in a few more of hers. Right now my training schedule is so full that something will have to give if I want to squeeze in another class.
It is definitely made a difference to my training. I now know when to push myself that bit more or when to pull back a bit.
The 'fat percentage of calories' is also interesting and I still have to learn more about this and what it means exactly. But it varies greatly between Spinning & Personal Training. With Personal Training I can burn less calories but have a higher fat % and with Spinning and Zumba burn more calories but the fat % is less.