I'm afraid to, I've had dizzy spells on the elliptical and treadmill when I really got my heart raising. One time I got a funny feeling (not pain, just weird indescribable) in my chest while it was happening and I was afraid it was my heart.
Is that a valid concern?
Eh, fake heart pains and go to the ER. They'll give you the EKG, etc and you can make sure you have no unnoticed problems
How high did you get your BPMs? Keep it low. You're not training for sports, you're trying to lose body fat while keeping heart healthy.
If you get bold for ECA, just roll with a half-dose. It's what I do. 1/2 a bronkaid, and 1/2 a caffeine. I've had decent abs even when gaining weight.
Don't bother with much of the OTC crap. caffeine and a little jolt, but you can drink a cup of green tea with 1/2 yello caffeine before workout and get the same. Only supps I'd use are creatine and whey of course.