I agree with Killz and Iron man. Conditioning is your best bet. At my first MMA training session, a few years ago, I gassed badly and quickly. I was almost vomiting at one point. Long distance running is almost pointless for MMA. The only use being it will strengthen your lungs somewhat. Running steps is perfect. Interval training, burpees, squats and lunges are all good too. Without a little conditioning your first few weeks are gonna be killer. Do you have any experience in martial arts? Wrestling or anything that might give you a leg up in terms of conditioning? If not, heed the advice given here and check out the training logs and tips on this forum. Everyone here is very helpful and accomodating so if you have any more questions feel free to ask.
I used to be Tyson Fury but now I'm not.