The Body-for-Life program consists of a meal plan and an exercise program that involves both strength training and cardiovascular training. The intent of the program is to boost your metabolism to help promote fast weight loss. Interval training is the theory behind the cardio workout. According to MayoClinic.com, this type of training naturally burns more calories than steady paced training. A treadmill is a good machine to use for this kind of workout because you can easily keep track of your speed and time.

Intensity Level

The Body-for-Life workouts revolve around intensity levels. They are based on a scale that goes from 1 to 10, with 10 being an all-out effort. You need to keep this intensity scale in mind when you do the interval workout on a treadmill. This is basically an estimation, but try to be as accurate as possible.

Warm up

The total length of the Body-for-Life interval workout is 20 minutes. This may not seem like very long, but interval training is intense, and this is plenty of time to achieve favorable progress. The first two minutes of the workout is a warm up. When you start the treadmill, move at a pace that is about 5 on the intensity scale. Depending on your current fitness levels, this can be anything from a light walk to a light jog.

Intervals

After your warm up is over, you are ready to do your intervals. These consist of four-minute cycles that start slow and become faster. As soon as you finish your warm up, increase the speed to an intensity of 6 and remain there for one minute. Then increase your intensity to 7 for your next minute, 8 for your next minute and 9 for your next minute. An intensity of 9 is just under an all-out effort. Again, if you are just starting out, this might only be a light jog. If you are in decent shape already, it might be a fast-paced run. Once you finish your minute at an intensity level of 9, reduce your speed back to what you used for an intensity level of 6.

Repeated Intervals

Once you finish your first round of intervals, follow the same pattern again two more times. After you finish your minute at an intensity level of 9 for your last interval, increase your speed one more time. This will be an intensity level of 10, which should be an all-out effort. Run this interval between minute 18 and 19. When you finish, reduce the speed back to what you used for an intensity level of 5 and remain there for one minute. You will have then finished your 20-minute workout.

Tips

Treadmills come equipped with an incline adjustment. For a variation, increase the incline with each interval instead of the speed. You also have the option of changing both the incline and speed. Before your workout, is it a good idea to spend a few minutes doing dynamic stretches. These are performed in motion and they acclimate your body to exercise movements, which prevents injuries. Perform stretches like leg swings, knee high raises, lateral lunges, alternating toe touches, ankle bounces and forward bends. During your workouts, make sure to use proper running mechanics. Keep your shoulders lifted, gaze fixed forward and do not place your hands on the handrails.