Studies show that you can increase the effectiveness of your exercise by varying the intensity of effort during your workout. This is readily accomplished in aerobic exercises such as walking, running, biking and swimming. It is not necessary to increase the amount of time spent exercising. Interval training simply gives you more bang for your buck.
In aerobic exercises, you should begin your work with a warm-up, as usual, ramp up into your normal pace to establish your heart rate and breathing rhythm, and then increase intensity by increasing speed.
• Maintain the increased speed for several minutes. You should be in this faster pace long enough to establish a new heart-rate and breathing rhythm. Really focus on your heartbeat and breathing, on how you feel in each interval.
• Maintain the interval for a measurable amount of time. Pick starting and ending landmarks to define a distance to maintain the new and different pace. Then slow down for several minutes.
• Repeat this pattern several times during your workout. It is not necessary to always strive for your maximum performance in the alternate intervals, just an increased effort for a sustained period several times during your workout.
The increase in intensity will not only result in great fat-burn for that session, it will also result in a higher resting metabolic rate after the workout is over. So you continue to burn calories at an increased rate even when at rest. The greater the intensity of effort, the more benefit you derive. It is also likely that you will increase your average workout pace with continued interval training.
The end result is a greater benefit in the same amount of time. And not only will your workout work harder for you, so will your rest.