i had done karate off and on since i was like 7 or so, but i went to my first mma gym at 17 and got so tired and so sick, i couldn't hold my hands up with my boxing gloves on them, and the trainer back then was quite a dick about it. i kept going though, and earned his respect a little, lol. I had been running a mile a day for about two weeks before i started, one that wasn't really enough, and 2 i made the mistake of eating before i went at 9 am. it was brutal. so if you want to build up your cardioo before hand do it, and don't eat to close to time to train. haha good luck.