Have any good info on cardio pulmonary resistance training and metabolism?

[Big Dave Smith]

After I get done competing, I'm scaling back my training to a M-W-F DC style split for a while. I'm going back to BJJ with the extra time, while at the same time beginning my off-season gaining.

I know my weight is going to soar this year. In order to be as cardio fit as possible, I want to begin doing elliptical/airdyne training with a gas mask or respirator to restrict breathing and increase my VO2 max.

I'd like to know more about VO2 max increases, how the body metabolizes nutrients (will it breakdown too much muscle? carb load before cardio?), etc.

Thoughts?
Anybody tried this?
Anybody have any studies?

Just looking for any kind of feedback possible. Thanks!