Wht is the "Afterburn" effect?


This post was nicked from top trainer Alwyn Cosgrove’s blog, read it, enjoy it and learn something. Over to Alwyn…….

Here’s a study I looked at recently and mentioned on the Real World Fat Loss DVD:

====Schuenke MD, Mikat RP, McBride JM.Effect of an acute period of resistance exercise on excess post-exercise oxygen consumption (EPOC): implications for body fat management.Eur J Appl Physiol 2002 Mar;86(5):411-7This group looked at the effects of circuit weight training on EPOC.The exercise routine consisted of three exercises (the bench press, the power clean and the squat), performed with 10RM loads as a circuit. The circuit was performed four times (i.e. twelve total sets) and took 31 mins.EPOC was elevated for 38 hours post workout. The duration and magnitude of the EPOC observed in this study indicates the importance of the role of high intensity resistance training in a fat loss program.====

This type of information should go a long way in helping fitness professionals design and implement effective fat loss programs. It’s not the workout – it’s the effect of that workout on EPOC.

EPOC stands for Excess Post-Exercise Oxygen Consumption and is defined scientifically as the “recovery of metabolic rate back to pre-exercise levels”. It can require several minutes for light exercise and several hours for hard intervals.

In layman’s terms it means you keep burning calories at an increased rate after a workout.
If you can imagine a big forest fire, you understand that it doesn’t just burn for an hour and then burn out – it gradually burns out so that over time there is no fire anymore. The “peak” of the fire may have been hours ago, but there is still flames being produced for a long time afterwards.

We call this Afterburn – metabolic disturbance – elevating EPOC to maximize caloric burn for the other 23+ hours per day. Is there much of a real world effect of burning 300 calories per workout (e.g. aerobic work) if I don’t elevate EPOC?

If we could elevate EPOC even an apparently insignificant 1/4 of a calorie per minute for the 38 hours that the study showed, then that 31 minute resistance training workout would burn maybe 300 calories during the session plus an extra 570 calories over the next 38 hours. That becomes very significant.

In the past – fitness professionals and researchers have looked at how much fat is burned during the exercise session itself. This is extremely short-sighted.

As my colleague Alan Aragon said:
“Caring how much fat is burned during training makes as much sense as caring how much muscle is built during training.”Think about that. If we looked at a weight training session that started at 9am and finished at 10am – how much muscle would we see built if we stopped looking at 10am? None.In fact – we’d see muscle damage. We could make the conclusion that weight training does not increase muscle – in fact it decreases muscle right? It’s only when we look at the big picture – and look at the recovery from the session – that we find the reverse is true – weight training builds muscle.

Fat loss training is the same way. Someone talking about the benefits of the “fat burning zones” or “fasted cardio” is a sure sign that the individual has stopped looking at the end of the exercise session. They have come to the conclusion that fasted, lower intensity steady state exercise burns the most fat and made a massive leap of faith to suggest it is best for real world fat loss.

Using that same logic these same people would suggest avoiding weight training if you want to grow muscle.

Take home message – focus on the Afterburn effect not just what happens during the exercise session.

–AC

PS – My question is – could we get ANOTHER EPOC boost if we train less than 38 hours later? Could we raise an already elevated metabolism further? These are the questions that keep me up at night….
PPS – well that, and what the hell is that black smoke monster on ‘Lost’…..
posted by Alwyn Cosgrove at 5:42 AM

Get on to Mr Cosgroces homepage www.alwyncosgrove.com for more top class info from one of the leaders in the field of training, exercise and fat burning.

Wild Geese
www.wildgeesema.com
www.wg-fit.com
every cause but our own

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