Britney backstage on People magazine

For most people, the idea of working out for more than six hours a day might sound like nothing short of torture.
But Britney Spears can’t get enough. For the last six weeks, she’s been training for 90 minutes a day, followed by another five hours of dance rehearsals in preparation for her North American tour, kicking off June 16 in Sacramento.
“I’m pumped up!” Spears tells PEOPLE inside her cozy dressing room on the Sony lot in Culver City, Calif. “We’ve been working hard. And the costumes are coming next week. This is the exciting part, when all the pieces – the masterpiece – come together.”
During Spears’s month and a half of prep time, trainer Derek DeGrazio has cooked, packaged and labeled meals (like baked fish and broccoli) and snacks (such as celery with almond butter) for the 29-year-old pop star, six days a week.
She does get a break from all the discipline, though. Sunday, says Spears, is her “cheat day.”
But it’s certainly not derailing her efforts. Spears’s workouts and her 1,500-calorie-a-day nutrition plan have whipped her into top tour shape.
“You can see the tone in her muscles – her arms, legs and abs,” says DeGrazio. “She looks amazing.”