Ghostbusters alum Ernie Hudson is working harder today than he ever did taking down Gozer.

In 2016, the 71-year-old—who looks 20 years younger—was on the road for 50 out of 52 weeks to film three TV shows in New Mexico (Graves), Los Angeles (Grace and Frankie), and Chicago (APB), as well as traversing the country for speaking engagements and visiting his family in New York and Minneapolis. Regardless of all his travels and work, Hudson finds time to fit in a healthy lifestyle.

“I’ve got a gym at the house and a trainer in L.A.,” says Hudson, “but I haven’t been able to be in one location.” 

Still, the lack of consistency poses no challenge for the former Marine, who pumps out “at least 100 to 150” pushups across three sets. On the other days, Hudson squats. While traveling, Hudson jumps rope and fits in crunches or planks in his hotel room. He’s also besotted with his Fitbit, trying to achieve his 10,000-step daily milestone.

Despite all the activity, Hudson does admit that it’s difficult to fend off Father Time. “I used to be able to jump, like, five feet. Now my legs only come off the ground about a foot. I see it in my friends. You go back to your high school reunion, and you go, ‘Holy shit, what happened?’”

Hudson’s midsection does have some paunch, but struggling to keep the weight off comes with age—he’s currently 222 pounds and would like to get down to 210. He’s tightened up his diet, eating more whole foods like vegetables and lean proteins and avoiding processed foods like refined breads and pasta. “If we had a hand in it, it’s probably screwed up,” Hudson says.

The former warden on Oz, Hudson will take on his latest role in Fox’s new drama APB. The show, inspired by a New York Times article about a wealthy entrepreneur in New Orleans who used his own money to start a high-tech police force, takes place in crime-riddled Chicago, with Hudson playing the about-to-retire Capt. Ned Conrad.

“I worked in the old system for years, learned the politics, not really happy with it, and then this billionaire who loses a friend to a shooting comes in. Everybody is skeptical, but there’s a part of him that feels like, What if it could work? My job is making sure he doesn’t go too far.”

Part of the advanced technology to combat the corruption, police shootings, and cover-ups include drones, better Tasers, and an app that replaces the old 911 system.

While filming APB, and all his other shows and movies, Hudson can be found walking around the set in between takes. He also walks around all the airport terminals rather than indulge in the free snacks at the first-class lounges. It’s been paying off, too, as Hudson shows no signs of calling “cut” on his acting career.

“I certainly don’t want to be in bad health because of something I didn’t do, or suddenly I’m weighing 350 pounds and I’ve got to walk around with an oxygen tank,” Hudson says.

Tune in: APB airs Mondays on Fox at 9 p.m. EST.