Updated January 28, 2015.

The 'afterburn', or the amount of energy you use after you stop exercising, has been promoted as an important slimming idea. If you can get afterburn, which is really another way of saying your metabolism increases for several hours or longer after a particular exercise, then that's a bonus because you burn fat during the exercise and after you cease as well. The extra oxygen required to return your system to rest in the post-exercise recovery period is the basis of the afterburn.


Exercise scientists call this afterburn effect EPOC, which stands for Excess Post-exercise Oxygen Consumption. The authors of one study (LaForgia) say that the high intensities required -- greater than about 75 percent of maximum heart rate -- are probably beyond what most people wanting to lose weight can cope with in sustained exercise. So the afterburn advantage from lifting weights or running fast is there, but you need to be able to sustain that intensity, which means a lot of hard work.

Weight Training or Aerobics?

Although weight training tends to be promoted most as the most efficient producer or EPOC, this is not necessarily correct. Ultimately, it depends on how you train. Exercise intensity is the key. In weight training that tends to mean lifting heavy weights in sessions approaching 3 sets of 10 lifts at about 80% of your 1RM, that is, your maximum lift for any exercise. If you've done this sort of resistance training, then you will know it is heavy duty stuff.

On the aerobic front, running, cycling, rowing etc, you really need to work above 75% maximum heart rate to generate useful afterburn.

(This is when you cannot comfortably talk and you sweat readily.)

The intensities above are in the useful EPOC zone. Naturally, it gets even better when you add sufficient volume. One hour is better than 30 minutes.

Type of Weight Training Exercise

Recently, various resistance exercises have been tested comparatively for how much EPOC they might generate. As might be expected, exercises that use multiple and or large muscle groups tend to generate more afterburn. These are the full-body exercises like squats, deadlifts, hang cleans, push presses and all the other pieces and variations of the Olympic lifts like clean and jerk and the snatch. Upper body exercises like the bench press don't seem to generate as much EPOC.

Ultimately though, what you need to do is work at a relatively high intensity and volume at any activity to generate a useful degree of metabolism up-regulation.

Sources

J Hum Kinet. 2014 Oct 10;42:235-44. 2014. Oxygen uptake and heart rate kinetics after different types of resistance exercise. Vianna JM, Werneck FZ, Coelho EF, Damasceno VO, Reis VM.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4234762/

Eur J Appl Physiol. 2014 Sep;114(9):1809-20, 2014 May 31. Effect of exercise intensity on post-exercise oxygen consumption and heart rate recovery. Mann TN, Webster C, Lamberts RP, Lambert MI.

Sports Sci. 2006 Dec;24(12):1247-64. Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. LaForgia J, Withers RT, Gore CJ.