Editor's Note:  I was always under the impression that a workout that consists of high intensity exercises first, followed by low intensity exercises burns the most fat in the shortest amount of time. This recent article by Christian Finn, however, says that might not necessarily be the case... 

It's the same old story. You promise yourself to exercise more but the main challenge remains - trying to fit exercise into your busy schedule.

Most point to a lack of time as the main reason why they can't stick to a regular exercise routine. That's why programs such as 8 Minutes in the Morning or The Slow Burn Fitness Revolution have become so popular. They promise to help you get in shape in less time and with less effort.

Recently, I've had a lot of questions about a technique called dual-rate exercise. The idea is that you burn more fat during your workout (and, in theory, lose fat faster) without exercising longer or harder.

Let's take a closer look at the research to see what it means for you.

Researchers from the College of New Jersey had college-age volunteers (eight men and four women) visit the lab on two occasions. They measured total calories and fat calories burned during 30 minutes of exercise on a stationary bike [2].

Visit #1 (low-to-high):
The subjects exercised at a low intensity (about 60% of their maximum heart rate) for the first 15 minutes. For the last 15 minutes, they trained at a higher intensity (roughly 80% of their maximum heart rate).

Visit #2 (high-to-low):
After a brief warm-up, subjects started at a high intensity for the first 15 minutes, and finished the last 15 minutes at a low intensity.

There wasn't much difference between the two workouts in terms of total calories burned (280 calories for workout one versus 272 calories for workout two).

However, the volunteers burned roughly 23% more fat during the high-to-low workout. This is the finding that's caused all the interest in dual-rate exercise.

So, should you use a high-to-low exercise sequence in your next workout?

There's certainly no harm in trying it. But I'm not convinced that it'll make much difference to the amount of fat you lose.

Why?

Firstly, you burn more fat during the post-exercise period with high- rather than low-intensity exercise. I'm guessing that if the researchers had measured fat metabolism during and after exercise, there wouldn't have been much difference between the high-to-low and low-to-high workouts.

What's more, this is just one study. And the results haven't been replicated in other trials.

Researchers from Brunel University, for example, measured fat metabolism during two different workouts [1].

Workout one involved 15 minutes of high-intensity exercise at 75% VO2max, followed by 40 minutes at a low intensity - 50% VO2max. Workout two comprised 40 minutes of low-intensity work, followed by 15 minutes of high-intensity work.

Unlike the earlier study, the results show no significant difference in the number of fat calories burned during either session.
The bottom line

There's certainly nothing wrong with dual-rate exercise. In fact, the fat-burning program I use follows a "high-low-high-low-high" pattern (see How to fight fat and win in the Members-Only Area).

But don't get distracted by every new "wonder" program that you read about. Most people who try chasing every rabbit that crosses their path end up suffering from paralysis by analysis. They get confused by all the different ideas and theories, and end up doing nothing.

It's a lot more important to work hard and be consistent, than to waste your time and energy second-guessing whether the program you're using is "right" or "wrong."

Read other articles by Christian Finn

About the Author

Christian Finn is a Certified Personal Trainer and holds a masters degree with distinction in exercise science. He's lectured at a number of universities and private training organizations around the United Kingdom on fitness training, weight loss and the effective use of nutritional supplements. He writes extensively on the subject and his articles have been published in numerous magazines, leading industry journals and websites worldwide, including Men's Health, Men's Health Muscle, Fit Pro (April/May 2001), CAM magazine (February 2003), Image (January 1997), Zest (March 2004), and Body Life magazine (March/April 1997). He was also featured in the July 2004 issue of Muscle & Fitness (UK edition). His website, TheFactsAboutFitness.com, is dedicated to providing its members up-to-date, unbiased information and research on the world of fitness.

References

1. Egan, D., & Head, T. (1999). Energy substrate metabolism during dual work rate exercise: effects of order. Journal of Sports Science, 17, 889-894
2. Kang, J., Schweitzer, J.S., & Hoffman, J.R. (2003). Effect of order of exercise intensity upon cardiorespiratory, metabolic, and perceptual responses during exercise of mixed intensity. European Journal of Applied Physiology, 90, 569-574