I'm a bigger guy, 6 foot tall, about 250 pounds, go to an MMA gym 3-4 times a week (more when time allows) and a regular gym once or twice a week. My boxing/kickboxing/Muay Thai is on point, both for power and accuracy, but my cardio is horrendous, especially when doing live rolls in Brazilian Juijitsu. What would be the best way to increase my cardio capacity without losing my striking power?
Note 1: I don't think at my age and with my previous KOs making me a bit scatterbrained at times I'll be actually taking a fight, but it would be nice to not huff and puff when live rolling or for going longer than about a 5 minute round on the bag.
Note 2: I also belong to the martial arts stack exchange but I felt this would be better suited for general fitness
Thanks in advance for any advice