Kevin Hart works out like a pro athlete. His trainer says heavy lifting isn't the key to staying shredded.

• Kevin Hart spends hours in the gym each week, according to his personal trainer Ron "Boss" Everline.
• His initial goal was to get on the cover of fitness magazines, but now he trains for longevity.
• His routine includes sprinting and full-body weight training to build muscle and fitness in his 40s.

At 4:30 a.m. you'll find Kevin Hart in the gym.

While he's best known for being a comedian and actor, Hart trains like a serious athlete: six days a week, about an hour and a half a day, no excuses.

It started over a decade ago, when Hart approached trainer Ron "Boss" Everline with a pitch to break into the fitness industry in major way.

"He wanted to get on the cover of Men's Health," Everline told Business Insider. "I said I'm the man to help you get there — if you listen to the rules."

Everline's rules are simple: lifting weights, high intensity exercise, and consistency get results.

And he delivered. Hart made the cover of Men's Health in 2015, then again in 2020, and plenty of other magazines in between.

Now 46, the star is still going hard in the gym, and his workouts prioritize longevity more than ever.

"Age doesn't really factor into what we're capable of. Training in a certain fashion keeps you young and vibrant," Everline said. "The workout, to me, stays the same. It's how much you load up."

His rules for getting shredded haven't changed: here's his best advice to get in shape for years to come.

Lift weights — the right way

Everline started his fitness aspirations with dreams of going pro in the NFL, and kept his mindset of training like an elite athlete.

His workouts with Hart incorporate full-body training for speed and power, with moves like squats, cleans, presses, and lunges. A typical week focuses on leg exercises on Monday, chest exercises on Wednesday, shoulders and back on Thursday, and full-body Friday and Saturday (with an active recovery day for light cardio on Sunday).

Over the years, the exercises haven't changed much, but Everline said their approach is less about lifting as heavy as possible and more about building resilience.

"The lifting now is more tailored toward more mobility and stretching. As you get older, it's less load," he said. "Muscle is a foundational principle as you get older. The more muscle you have, the better you are.

Everline, 41, said that the key to progress with weights is to challenge your body with quality reps to put your muscles under stress over time, but you don't need to go all-out.

"Lifting super heavy, it's not necessary for growth. It's really time under tension," he said.

Don't skip the warm-up

The biggest change between working out in your 40s is that you can't just walk into the gym and start throwing weights around, according to Everline.

"I think there's a lot more warming up and getting the body primed versus when you're 25, you just go into the gym and go," he said.

Warming up at the gym prepares your body to perform the same movement patterns you'll be doing in the workout, and activates the right muscles to make the most out of your workout and prevent injury.

Start sprinting to stay young

Hart's workout routine includes plenty of high-intensity interval training (HIIT) on full-body workout days.

"We sprint a lot to get our heart rate up and keep us super young," Everline said.

Drawing on his athletic background, Everline puts Hart to work with outdoor running sessions at the track with repeated intervals of 100 or 200 meters, supplemented by some 1-minute treadmill sprints.

Extensive research shows getting your heart rate up for short bursts is a great way to prevent disease and even helps to stave off aging.

"Most people don't sprint after a certain age," Everline said. "If you continue to use it, you can still run a sprint when you're 50 or 60, and that's why it's a foundational principle for us."

Get a little competitive

A bonus of Hart's high-intensity routine is that it taps into his naturally competitive spirit, making the workouts fun and motivating.

"It keeps the gamification a part of how we train at a very, very high level," Everline said.

Finding ways to push yourself, and have a good time doing it, is the key to sticking with a workout long enough to see results. But when it comes to getting motivated, there's no one-size-fits-all, according to Everline.

"It's really finding a formula that fits you, taking it day-by-day, and not trying to have all the answers at once," he said. "That's what longevity is built on. It's the compound effect of doing small things over a period of time."