Q&A on the Afterburn Effect

Q: Alwyn, the latest issue of your newsletter was fantastic. EPOC explains the "Afterburn" effect with clear scientific reasoning. It's the explanation that I had been looking for a long time. When discussing training and fat loss with the general public I usually struggle to get the point across with any significant level of clarity. The person is also more confused by the exposure to the new information. Your article provides great points that can be translated (when needed) so that the average Joe or Jane can grasp them effectively. I do have three questions:

1)How do you determine when a client is deconditioned to the point where steady-state aerobics should be used?

2)During the 38 hrs. of observation did the EPOC level decline steadily or was there a marked point where it noticeably dropped off?

3) Do you have a reference comparing cardio - interval training to steady state
training?

Seriously, that was the BEST explanation of training for fat loss that I have ever seen. Everyone should read it.

A: To read my explanation of Afterburn and the EPOC effect - click here.

1) I use resistance training to establish a physical structure (i.e. correct imbalances etc) that can handle intervals or higher intensity aerobic training first - you can get a cardiovascular effect using resistance training based models. For fat loss clientele I don't use steady state work very much. Remember - interval training can be alternating periods of brisk walking with just standing still - it doesn't have to be kettlebell swings and sprints.

2) The study I mentioned checked at 90 mins, 24 hours and 38 hours I believe. As with most EPOC studies, they don't monitor metabolism constantly. They did find (in this study) that metabolism was back to baseline within 43 hours.

However - if you alternated resistance training and interval training every 24 hours - I am pretty sure that you will be elevating an already elevated metabolism - compounding your results. EPOC increases linearly with duration, but exponentially with intensity. So intensity is the key when we are discussing fat loss training - NOT duration.

3) The landmark study comparing high intensity intervals came from Tremblay.

The premise of the study was to compare twenty (20) weeks of steady state endurance training and fifteen (15) weeks of interval training.

When comparing total calories burned the researchers found that the energy cost of the endurance training was 28661 calories, while the total calories burned in the interval training program was 13614 calories. In other words the interval training group burned less than half the calories of the endurance training group.

However, despite its lower energy cost, the interval training program induced a more pronounced reduction in subcutaneous adiposity compared with the endurance training program.

And when the researchers adjusted the results and corrected for the difference in energy cost, the interval training group showed a NINE TIMES greater loss in subcutaneous fat than the endurance group.

Additionally the researchers noted that the metabolic adaptations taking place in the skeletal muscle in response to the interval training program appear to favor the process of fat oxidation. Lyle McDonald and i discussed this last week - perhaps the additional fat lost is NOT a result of EPOC as we initially believed - but an increase in the level of fat burning enzymes. Either way - the results is the same - increased real world fat loss (watch out for the manual of the same name to be launched soon!).

A follow up study came from the researchers, Trapp & Boutcher put subjects through a 15 week study where one group was a control, one group did interval training (20 minutes of alternating sprints and recovery), and one group did 40 minutes of slow cardio.

The interval group lost 2.5kg of fat in 15 weeks on average (with one subject losing 7.7kg of fat), while the slow cardio group lost only 0.4kg of fat over 15 weeks on average. So the interval group spent half the time training and received over six times the results. Do the math.

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AC
PS - If you are interested in a practical approach to combining all this data into an actual program - then check out www.afterburntraining.com