Interval training simply means increasing and decreasing the speed or intensity of your exercise throughout your workout. You might perform the activity at a higher speed for a few minutes and then slow your pace to recover. The amount of calories you will burn during an interval workout will depend on several factors, including the type of exercise you are doing, the speed and duration of your intervals and your weight. Determining how many calories you are burning can help you decide if you need to adjust the intensity of your intervals to meet your fitness goals.
Determine what activity you want to do, which will affect the amount of calories you burn. Virtually any form of exercise can be transformed into an interval workout. You can perform intervals on the elliptical, stationary bike or treadmill, or you can make use of your neighborhood sidewalks and perform intervals while walking or jogging.
Decide what intensity levels you want to work in. In general, the faster and more intense the exercise, the more calories you will use. Healthy adults need about 150 minutes of moderate cardio exercise or 75 minutes of vigorous cardio exercise each week. However, if you are new to exercise, you may have to work at a lighter intensity until you build stamina and strength.
Figure out what speed you are working out at. For example, if your workout consists of walking and it takes you 15 minutes to walk one mile, this means your speed is 4 mph, and a person who weighs 125 pounds will burn 135 calories in 30 minutes at this pace. If you want to include intervals of jogging, calculate how long it takes you to run a mile. Performing a 12-minute mile means you are working at a speed of 5 mph, and a person who weighs 125 pounds will burn 240 calories in 30 minutes at this pace.
Add up the amount of time you spend at a higher intensity interval, as well as the amount of time you spend at the lower intensity. A typical interval workout may include 30-second bursts of higher-paced activity, followed by two-minute recovery periods. For example, a 30-minute walking and jogging workout might consist of six minutes total of jogging at 5 mph and 24 minutes total of walking at 4 mph. This means that the 125-pound person will burn 156 calories during this interval workout.
Adjust your calorie-burn calculations as you gain stamina and increase the duration of your higher-intensity intervals. For example, the 125-pound person doing a 30-minute workout may increase her jogging intervals to one-minute durations while keeping her walking intervals at two-minute durations. This would mean she spend 10 minutes jogging and 20 minutes walking, increasing her total calorie burn to 170 calories.