You work hard to stack on muscle and the thought of sweating through cardio makes you cringe—maybe because you hate clocking time on the treadmill, or because you fear your well-earned muscle will take a hit. Well, we’re here to change that mindset

Sure, if you run 80 miles a week and never touch a weight, you’ll certainly drop muscle—and fast. But, a certain amount of strategic cardio is not only safe, it’s smart. In fact, cardio can boost cognition and add three years to your life. And better yet, it doesn’t have to suck.

We found eight ways to make cardio more “fun” (or at least not quite as mentally painful)—each with a fat-burning, muscle building) workout routine, all designed by certified personal trainer Kenneth Valentin.

“The key to getting lean and sustaining your muscle mass, is by performing exercises that combine strength training and cardio,” says Valentin.

From flipping tires to pushing sleds, these killer cardio workouts will build muscle, boost endurance, and shred that layer of excess fat—for good.