Excess Post-Exercise Oxygen Consumption: How Important Is It?
For years it seems the usefulness of excess post-exercise oxygen consumption, or EPOC, has been exaggerated. In discussions I have regarding training, EPOC still comes up quite a bit, as though it is some magical aspect of conditioning that makes some training regimens leagues above the others. For example, EPOC is often one of the major justifications for frequent high intensity interval training, despite evidence to the contrary for trained athletes.
Nevertheless, the proponents of EPOC persist. Indeed, it’s not as if EPOC isn’t a real thing, but statements about how effective it is in terms of burning any substantial amount of calories are dubious at best. To stimulate EPOC to any significant degree at all requires workouts that are probably too intense for most serious athletes to do frequently anyway. In fact, in a study this month in the Journal of Strength and Conditioning, researchers looked at how high-intensity weight training stimulated EPOC in trained athletes.
Resistance training, naturally, uses greater intensities than most forms of cardiovascular training. Because of the disruptions to acid balance, muscle fatigue and damage, and substrate utilization, weight training has the potential to stimulate EPOC more than cardiovascular training. EPOC is the result of the body expending energy to recover from disruptions to homeostasis, the balance maintained by the body. The greater the intensities, the greater the disruption.
For the purpose of disrupting homeostasis, the researchers used two protocols. In both protocols the weights used were about 85% of maximum for 6 to 8 reps. The workouts were total-body and included squats, deadlifts, rows, and bench presses. When multiplying the reps and the weight used, one of the groups was lifting a total of 10,000kg (22,046lbs), and the other was lifting twice that at 20,000kg (44,092lbs). That’s quite a bit when you think about it. According to the workout design, if I were using 300lbs for my squat, that would be some 8 sets of 6 or 7 reps, and the athletes only had two minutes of rest. And that’s just one out of four exercises. Indeed, the group with more volume spent an hour and a half lifting 85% of their maxes.
In the study they used well-trained athletes. They did so because although such routines seem to boost EPOC pretty well in sedentary people, for trained people the results may not be as significant. In fact, the results of this particular study weren't so great. Not only was there no difference between the two groups, but there was also no difference between EPOC before the workout and two days after the workout.
It seems that, even with a very intense workout, the EPOC for well-trained people simply isn’t a very important factor. There is no good reason to structure a workout to maximize EPOC unless you’re new to exercise. The good news is that we can keep our workouts focused on what our real goals are. If your goal is calorie expenditure, aerobic training combined with strength training and a solid diet is your best bet.
1. George Abboud, et. al., “Effects of Load-Volume on EPOC After Acute Bouts of Resistance Training in Resistance-Trained Men,” Journal of Strength and Conditioning Research, 27(7), 2013.
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