Ruth Bader Ginsberg wants to make sure she can defend civil liberties as long as physically possible.

The consistently liberal Supreme Court justice is 83—older than the other justices by three years. When US President Donald Trump nominated conservative judge Neil Gorsuch to fill the late Antonin Scalia’s position, many Americans started fretting about RBG’s health. Should she fall ill or become unable to do her job, the Supreme Court will likely swing right once more, a particular concern for liberals if Trump tries to overturn Roe v. Wade, as he says he will.

Luckily, though, Ginsberg is in better shape than most 83-year-olds (and possibly most people), according to Politico. Twice a week, RBG meets with Bryant Johnson, a 52-year-old ex-military personal trainer, who guides her through an hour-long workout consisting of some cardio, followed by three sets of 10 to 13 reps of weight training for her whole body—including pushups, which she does without the use of her knees, according to Johnson. She also does single-leg squats, and a standing maneuver where she throws a medicine ball to Johnson before sitting down and catching it—an exercise essential to allowing her to use the bathroom on her own, apparently.

There’s never actually a point when you’re too old to work out. In fact, you should work out for as long as you possibly can to help you in your daily life, as long as you don’t have any underlying conditions, saysKaren Smith, a dietician at Barnard Medical Center and personal trainer. Without regular exercise, activities like walking up or getting laundry can become impossible, and even dangerous, to do alone. “It’s really important to incorporate balance exercises, which can reduce the risk of falls, and strength training exercises, which help maintain healthy bones and may reduce the risk of fracture,” Smith says. Our bones naturally become more porous and brittle over time—especially in women. Most people don’t notice these changes until they fall and break a bone in an accident that previously would have only caused bruising. Fortunately, though, exercise puts a healthy strain on bones which can slow the osteoporosis process.

Last year, one 85-year-old completed (paywall) a full marathon—26.2 miles (about 42 km) in under four hours. And although Ginsberg’s workouts with Johnson have been a regular part of her life for a while now—indeed, she says her relationship with him is one of the most important in her lifeit’s never too late to start working out. John Schultz, an 84-year-old runner from Delaware, only started running when he was 60. According to a local papers, Schultz missed the bus coming home from work and decided to walk home until he realized jogging was faster. “What if I could just keep doing it?” he said. (He passed away last year after being hit by a car crossing the street—notably, not while running.)

So even though the notorious RBG may be getting up there in age, she’s at least making sure she takes care of herself to keep working her judicial bench at full capacity. When asked by Politico if President Trump, who is 70 years old and greatly enjoys fast food (paywall), could complete his workout, Johnson declined to comment.