Interval Training for Fat Loss

Tuesday, October 27th, 2009  |  Posted in In the News, Whats New  |  No Comments
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By James Walker, CSCS, Athletic Excellence | September 2007 Issue of Your Health Magazine

Have you ever considered interval training for fat loss? Athletes have been training this way for decades to enhance their performance and at the same time develop and maintain a lean physique. Interval training involves alternating lower levels of exercise with higher levels of exercise effort within the same workout. The lower effort parts are called active recovery because you are still moving or exercising but at a reduced effort. The higher effort portions are the actual interval or sprint components that art performed with a greater effort.

Intervals can be made to accommodate various types of athletic and fitness objectives and levels. Some forms include fartlek, pyramid, step and reverse pyramid intervals. The active recovery portions may last from one to five minutes depending on the level of fitness where as the interval or sprint portion will initially be shorter in duration lasting 15 second to three minutes.

Interval training will challenge both the aerobic (oxygen utilization) and the anaerobic (glycogen- muscle utilization) systems. More muscle utilization means more calories burned and fat loss. In addition you will tend to become fitter, stronger, and healthier in the process.

The American College of Sport Medicine and many other exercise science institutions have performed comparison studies using higher workout efforts vs. lower workout effort training. The higher the effort the more muscles need to produce that effort and the more energy used or calories burned. For example below is the energy-caloric output of a 150 Ib man walking, jogging, and running at different levels:

• Walking at 2-4 mph will burn 180- 300 calories per hour or 3.3 – 3.5 calories per minute.
• Jogging at 5-6 mph will burn 556- 690 calories per hour or 9.2 – 11.5 calories per minute
• Running at 8-10 mph will burn 920- 1050 calories per hour or 15 – 17.5′ calories per minute.
• As you can see caloric expenditure increases significantly as effort increases.

Interval training will allow the individual who can not sustain an 8 mph pace for an entire hour to train by alternating between 8 mph and 4 mph periods and burn more calories than by only going 4 mph. Thus the interval and higher intensity training is more time efficient for a given time duration.

So, if that person started out alternating at a 2: 1 ratio of a active two minute recovery period after a one minute interval period that same person would bum approximately 500 calories per hour or 7.5 calories per minute. Also, consider this, as the person’s fitness improves their interval ratios will improve as well. For example if the person began their intervals at 8 mph gradually they will improve to 8.5 to 9 mph, depending on their age, training, genetics, and athletic ability. It may be reasonable to get up to 10 mph. Like wise, their active recovery levels will increase from 4 mph walking to a 5-6 mph jogging.

The average individuals ability and fitness will improve eventually allowing them to go from the 2: 1 ratio to a 1:1 ratio, which would increase the calories burned by 30-50%. Finally, when just starting out consider doing low-irnpact intervals (pool, bike, elliptical, rower, sled, or walking-hiking hills).