At 78 years old, Rod Stewart is showing no signs of slowing down. The rock legend, known for ‘Do Ya Think I’m Sexy’ and ‘Handbags and Gladrags,’ still loves what he does, and is currently performing a series of dates in the United Kingdom before he launches the North American leg of his tour—after which he wants to pivot away from his familiar material and take on the Great American Songbook.

In a recent interview with People, the musician opened up about the fitness routine that helps keep him in peak performing shape as he prepares for his American tour dates and the next phase of his career.

“I work out extensively,” he said. “But I’m generally very fit. I’ve played soccer all my life, and I don’t smoke. It’s funny, critics keep saying on this tour, ‘Oh, he’s gone off the stage to have a rest.’ No I haven’t! I’ve gone off the stage because I’m wringing wet. I’m so bloody fit, you won’t believe it.”

Stewart reportedly trains around four times a week, and at least one of these workouts consists of the same kind of underwater drills used to train SAS members.

“You have a big rubber brick, and you’ve got to swim the length of the pool and push it the length of the pool, on the bottom of the pool,” he said. “It’s really wonderful. Well, sometimes it’s not wonderful because I don’t want to do it, but I’d say it’s fun.”