Make Your Cardio Work for You

Welcome to your aerobic countdown to a healthy body! This plan, created by Kevin Lewis, owner of State of the Art Fitness in Woodland Hills, Calif., incorporates two types of aerobic training, interval and steady-state endurance, for maximum results with no chance of boredom. And it's got one more bonus: You'll train indoors two days a week and outdoors the other two.

More important is the science behind the workout. It's based on monitoring your heart rate while exercising at different intensities.

"Doing cardio exercise without monitoring your heart rate is like strength training without knowing how much weight you're lifting or how many reps you're doing," Lewis says.

You can learn how to measure your maximum heart rate in the following pages. Meanwhile, here's why this program, which incorporates outdoor and indoor endurance and interval training, will keep your heart pumping -- and the calories burning -- for the next eight weeks.