Anybody do heavy bag for cardio? Not really sure you would call it cardio. I use to do it all the time like 4-5 times a week. I just started it up again. So basically 5 minute rounds with 2 minutes jump rope in between rounds so no real rest at all. Four rounds is about 1/2 hour. It's pretty intense and helps get the daily frustrations out. I's a heck of a lot more fun than working some cardio machine.