Alwyn Cosgrove, Fat Loss Expert and owner of Results Fitness, has compiled this short list of studies on the afterburn effect. EPOC (excess post oxygen consumption) is an increase in metabolism and caloric expenditure following strenuous exercise. The increased EPOC with interval based training is one of the main reasons why we use this as our mode of metabolic conditioning. From swings and kettlebell complexes, to agility work and bike sprints-our goal is to get you working hard (anaerobic) and let you subsequently rest, in order to initiate fat loss via metabolic boost and afterburn!

Take a few moments to read through the study excerpts.

NEW STUDIES ON EPOC (AFTERBURN)

Knab et al.
A 45-Minute Vigorous Exercise Bout Increases Metabolic Rate for 14 Hours.
Med Sci Sports Exerc. 2011 Feb 8.

These researchers had subjects undergo a bout of cycling at approx 73% of VO2 max (approximately 84% of max heart rate) for 45 mins.

The subjects burned on average 520 calories in the 45 min training session. The following day their resting energy expenditure was increased an average of 190 cals compared to normal. Basically – the subjects burned an additional 37% MORE calories than the workout itself in the 14 hour post workout period — meaning that a single high-intensity session, when including the post-workout metabolic boost could burn up to 710 cals in total.

A second study

Heden et al.
One-set resistance training elevates energy expenditure for 72 h similar to three sets.
European Journal of Applied Physiology. Volume 111, Number 3, 477-484, Mar 2011

The subjects were put on a very simple resistance training routine – full body training, either 1 or 3 sets per exercise of ten exercises.

The researchers then examined the subjects resting energy expenditure at 24, 48 and 72 hours post workout.  Both groups showed an elevated metabolism (afterburn effect) of around 100 cals per day.

But there was no difference between groups. It seems that it’s intensity that determines how many calories are burned post-workout, not volume (obviously a higher volume program would burn more calories during the session than a lower volume program.

A third study confirmed this:

Scott et al.
Energy expenditure characteristics of weight lifting: 2 sets to fatigue.
Appl Physiol Nutr Metab. 2011 Feb;36(1):115-20.

The researchers looked at the caloric expenditure of bench pressing using three different loads and concluded “As more work is completed (i.e., lower weight, more repetitions), aerobic and anaerobic exercise energy expenditures appear to increase accordingly, yet absolute EPOC remains essentially unchanged”. In other words – the post workout caloric burn (in this case measured aerobically)

One more:

Astorino et al.
Effect of acute caffeine ingestion on EPOC after intense resistance training.
J Sports Med Phys Fitness. 2011 Mar;51(1):11-7.

This study showed a 15% increase in post-workout calories burned after the ingestion of caffeine as a pre-workout supplement. The total extra calories burned as a result of this only added up to around 27 cals in the hour after the workout. Not a lot but still something to consider. Plus I like iced coffee 🙂

As usual my questions/ideas for real world application are:

What if we trained every 48 hours? Would we see a compounding effect of the additional calories burned post-workout?
What if we did full body training using free weights (kettlebells!) and multiple planes of movement instead of machines?
What if we paired exercises (studies have shown enhanced calorie burning during training with supersets)? Would that change things?
What about full body ground based exercises such as a squat or deadlift (the last study used a bench press)? Does that change anything?
What about exercises where not only the prime movers are being worked, but also the entire core? (all the time!)