Jennifer Aniston's Workouts and Yoga Practice

Always-in-shape Jennifer Aniston doesn't stay slim by thinking about fitness — she works for it. A source told Us Weekly, "She's obsessed with staying fit and young." During the filming of Just Go With It, in order to feel confident wearing a bikini on the set, she hit the Four Seasons gym every day for at least an hour, and sometimes more. A guest at the hotel said, "I saw her on the treadmill, and it was angled all the way up."

POPSUGAR Fitness tip: Up that incline, baby! Cranking the incline helps you burn more calories than if you keep the machine set to a zero grade. After a 30-minute workout at a 10-minute-per-mile pace, you'll burn 270 calories with no incline, 363 with a five percent incline, 420 with a 10 percent incline, and 482 with a 15 percent incline (crazy steep, I know). Not only will you burn an extra 100 calories or more, but the steep slope also helps tone your tush, thighs, and calves, problem areas for many women.