My cardio has gone from maintaining a long, steady pace to alternating fast and slow chunks. My trainer, Whitney Cole, said this burns more calories and works my cardiovascular system better than if I just kept the speed the same. Here’s the circuit I’ve been doing lately: I warm up on my elliptical for 10 minutes. Then I crank the intensity up and go as fast as I can for 2 minutes, then recover for 1 minute. I repeat the series two more times and then get off the elliptical and do some strength training moves for 5 minutes. I repeat the entire thing (10 minutes of intervals on the elliptical, 5 minutes of strength moves) two more times. When I’m done I’ve had a great, sweaty, calorie-torching workout!