Rev up your cardio

In this month's installment of our three-month cardio plan, you'll continue to get calorie-burning, body-strengthening, energizing exercise, whether you're working out or simply going about your everyday activities. Last month, with the progressive program designed by Tom Wells, P.E.D., F.A.C.S.M., your workouts emphasized building a fat-burning aerobic base -- plus, you discovered how upping your regular lifestyle movement can burn an extra 825 calories per week (without working out!) and improve your overall cardiovascular shape.

This month, though the changes in your workouts will be subtle, the physical benefits will be marked as you train your body to work at a higher intensity, ultimately allowing you to burn more calories with less effort. You'll also continue to introduce more movement into your life by doing activities that modern technological advances like computers, dishwashers and elevators have stolen from you. By the end of this month, you'll be two steps closer to looking and feeling your fittest, and primed for the final, calorie-blasting chapter.

THE PLAN

How it works
As described last month, you'll do three kinds of workouts in this program, adapted from a progressive "systems training" plan originally developed by exercise physiologist Jack Daniels, Ph.D. The plan is outlined in the Cardio Calendar and Workout Key below. (Note: If you missed last month's plan, you must do it before progressing to this one.) For each workout, try running or walking outdoors, swimming or working out on cardio equipment (set machines on manual so you can adjust the intensity). You'll have one day off each week, plus Lifestyle days on which you'll strive to burn calories with your everyday activities.

Warm-up
Begin workouts with 5-10 minutes of light cardio activity, like easy, brisk walking.

Cool-down
End each workout by stretching all major muscle groups, holding each stretch for 15-30 seconds without bouncing.