The smarter cardio workouts

General Directions
Select your cardio program according to your top fitness goal. If you have more than one goal, switch programs after 4-6 weeks. Do your program with the cardio machine or outdoor activity of your choice.

Intensity You'll gauge your intensity according to the Rate of Perceived Exertion (RPE) -- see below for guidelines. When told to increase your RPE, you can up the resistance, pace, level or incline, depending on the machine -- or, if you're outside, speed up or incorporate hills.

Calorie clues Note that the estimated calorie burn for each workout is based on a 145-pound woman, and ranges take into account a variety of activities and intensities. Calories burned per minute can be estimated using the chart at right.

Warm-up/cool-down Begin and end each workout with 5 minutes of low-intensity cardio (RPE 3). Note: This will add 10 minutes to your total workout time and 40-120 calories to the estimated calories you'll burn for most programs. In addition, after every workout, perform static stretches for all your lower-body muscles and your back, holding each stretch for 30 seconds without bouncing.

The Rate of Perceived Exertion (RPE)
With these cardio workouts, you'll gauge your intensity using the Rate of Perceived Exertion scale. Here's what the numbers mean:
RPE 1-2 Very easy; you can converse with no effort.
RPE 3 Easy; you can converse with almost no effort.
RPE 4 Moderately easy; you can talk comfortably with little effort.
RPE 5 Moderate; talking requires some effort.
RPE 6 Moderately hard; conversation requires quite a bit of effort.
RPE 7 Difficult; conversation requires a lot of effort.
RPE 8 Very difficult; conversation requires maximum effort.
RPE 9-10 Peak effort; no-talking zone

GOAL 1: BOOST ENDURANCE
Who it's for If you're training for a 5k fun run or bike-athon, or simply want to burn calories and get fitter, this endurance-building program is for you.

How it works Each week, you'll do two different interval workouts, varying the intensity in slightly different ways. By working close to your anaerobic threshold (the point at which you become breathless), you build stamina. As your fitness level improves, you'll be able to work at a higher intensity whether you're running a race or taking a Spinning class, which will translate into more total calories burned.

Workout schedule Do the following High-End and High-to-Low interval workouts 3-4 times a week total (once or twice a week each). Take a day off between workouts or, if desired, do 30-45 minutes of moderate-intensity (RPE 4-6), steady-state cardio once or twice a week. Don't do 2 interval days in a row; take at least 1 or 2 days off a week to recover.

High-End Progressive intervals maintaining higher levels of intensity.
Time: 4 min. RPE: 5
Time: 4 min. RPE: 6
Time: 3 min. RPE: 7
Time: 3 min. RPE: 8
Time: 3 min. RPE: 7
Time: 2 min. RPE: 9
Time: 3 min. RPE: 7
Time: 3 min. RPE: 8
Time: 3 min. RPE: 7
Time: 4 min. RPE: 6
Time: 4 min. RPE: 5

Total time: 36 minutes
Calories burned: 204-582, depending on activity

High-to-Low 8-minute intervals, going from moderate- to high- to low-intensity
Time: 4 min. RPE: 6
Time: 1 min. RPE: 8-9
Time: 3 min. RPE: 3-4
Repeat entire interval 5-6 times total.

Total time: 40-48 minutes
Calories burned: 258-702 (48 minutes)