Interval Training: The Future of Cardio Conditioning

There has been much debate regarding whether or not interval (variable intensity) training is any more effective than the steady-state cardio approach that has been recommended for decades.   While the jury may still be out to some extent, there is compelling evidence that supports interval conditioning as a safe, effective, and highly-efficient method of exercise for people of all ages.  If you’ve never heard of interval training before, here is an explanation and some of its benefits.

Interval training, sometimes called high-intensity interval training (HIIT), involves a combination of high and low-intensity training within a single workout session. In this session, a higher intensity effort is followed by a lower intensity or “active recovery” period and then repeated. This type of training is in contrast to the more familiar “steady state” exercise where the intensity is much lower but longer in duration. Interval training can be  excellent for fat burning, as well as cardiovascular conditioning, but let’s have a look at some more reasons to use interval training for your cardio workouts.

Benefits of Interval Training:

1. Intervals vastly reduce boredom. Traditional steady state cardio training can become quite boring. Interval training offers more variety and excitement to your workouts.  In addition, the variable intensity nature of the exercise is more consistent with most recreation and daily activities.  Essentially, training through a much broader range of cardiovascular demands.

2. Interval training increases post-exercise energy expenditure (calories burned following exercise) more than steady-state exercise, which means that more fat is burned. After intense exercise, the body needs extra calories as it works to repair muscles, replace energy stores (i.e. carbohydrate) and restore the body to its normal state (e.g. reduce heart rate). This can take many hours so you will burn more calories long after the workout is over. While the precise duration of elevated post-exercise metabolism is debatable, research shows that metabolic rate can be higher for several hours following interval training compared to steady state exercise.

3. Interval training stimulates the respiratory system, cardiovascular system and nervous system to a greater degree. Therefore, more fat and carbohydrates are burned to support the expanding energy demands of the body during, and after intense exercise.

4. Interval training increases the activity of enzymes involved in fat burning. Research has shown that after a bout of interval training there is more fat in the blood (i.e. free fatty acids), which is an indication of more fat, being used for energy production.

 5. HIIT burns more calories. As an example, 30 minutes on an Elliptical machine using a steady state program will burn roughly 292 calories, whereas 30 minutes of intervals will burn approximately 584 calories!

6. HIIT is heart healthy and causes a greater increase in VO2max (aerobic capacity). By stimulating your cardiovascular system to work closer to its maximum capacity for a longer duration than steady state exercise.

7. HIIT allows for better time efficiency. For instance, a typical 40-minute steady state ride on a bike could be reduced to 20 minutes of HIIT, due to its demands on the aforementioned systems.

8. HIIT results in increased amounts of circulating growth hormone (GH) following exercise. This promotes an increase in lean body mass and increased fat burning. This does not occur to the same extent with steady state exercise. This is particularly beneficial for those looking to maintain their muscle mass and at the same time reduce body fat.

9. Interval training makes use of both aerobic (type 1) and anaerobic (type 2) muscle fibers. This is in contrast to steady state exercise that only makes use of type 1 fibers. By increasing the conditioning of these type 2 muscle fibers you will greatly increase your capacity to tolerate high-intensity exercise/activity, which means an increased opportunity to exercise at levels that burn more calories.

10. Because of the high-intensity of this exercise and the increased use of anaerobic type 2 muscle fibers there is an increased use of the body’s glycogen (muscle-stored carbohydrates) stores. This is very beneficial for fat loss as the body will conserve carbohydrate following exercise and thus use fat as an energy source for the body’s energy requirements. The more glycogen you use during exercise the more fat you will burn following exercise!

In addition, some other potential benefits of interval training when compared to steady state endurance training are as follows: increased anti-oxidant protection, improved immune function, reduced risk of joint wear and tear, reduced muscle wasting, increased residual metabolic rate following exercise, and an increased capacity for the heart to handle life’s every day stressors.

While interval training is certainly no substitute for properly performed strength training, it is an ideal complement and provides everything needed to achieve optimal cardiovascular health.  The Appleton Fitness for Life, Inc. staff of personal trainers develop personalized interval programs so that each individual can safely reach his or her fitness goals as quickly as possible.   In addition, the AFFL Condensed Cardio Program provides this method of trainer-directed exercise without the distractions associate with a multi-service health club and at a fraction of the cost of other personalized programs.

Remember to always consult your physician and a qualified fitness professional when starting any fitness program or changing the demands of your existing program.

“Exercise Smarter and Harder!”