Thursday, February 10, 2011

Fat Loss Theory: Running and Aerobics (Part 1)

Part 2

It is a widespread belief that aerobic exercise, such as running, is necessary for fat loss. This all got started shortly after Dr. Kenneth Cooper's book Aerobics was published in 1968.

For some reason, aerobic exercise became a widespread phenomenon in the 1970s... and unlike other trends and fads, aerobics had staying power. Interestingly enough, the 1970s was also the time that bodybuilding went mainstream (thank you Arnold).

I could rant about how these two styles of training ruined fitness for decades (and will continue to do so)... however, I will instead take the objective road. Since I've already written about bodybuilding splits not being conducive to fat loss, this series of posts will analyze running/aerobics and their effectiveness as a fat loss tool.

As with my popular/controversial P90X series, the first thing we need to put running/aerobics up against is the theory of absolute intensity, which, in case you are new to this site, states, "The greater the absolute intensity you achieve with training, the greater the fat loss result will be."

But before I dive into that matter specifically, I have to address something very important. Aerobics and cardiovascular exercise ARE NOT the same thing! In Chapter 18 of The Theory of Fat Loss, I have a comment box that addresses this issue specifically. It reads...

"Cardio is any type of exercise that significantly raises your heart rate and keeps it up for a prolonged period of time. Essentially, any type of exercise can be considered "cardio" if it fits that requirement. Aerobic exercise is exercise that primarily utilizes the aerobic energy system for work periods. Circuit weight training and most forms of interval training are "cardio" but are not "aerobics."

For something to be "aerobic" it MUST be low intensity! You see, for aerobic exercises (such as distance running) to actually be aerobic, they must not stress the anaerobic energy systems to a great extent. The anaerobic energy systems only kick into high drive when the aerobic systems are unable to provide our bodies with energy at the rate we need that energy.

*Note: I've never seen a value for how much the aerobic energy system needs to contribute for an exercise for it to be considered aerobic. If there is one... someone let me know (comments, email, etc.).

**Note 2: I make the point about aerobics vs. cardio for two very specific reasons. First, it is ridiculous to separate cardio from other forms of exercise like most people do. All exercise will raise your heart rate, and thus all exercise can be used to strengthen your heart (you just need to program volume and rest time appropriately). Nobody NEEDS steady state exercise for any reason. If they enjoy it, that's one thing... but it is hardly an ideal method if your goal is a healthy heart. Second, most "aerobics" classes are completely mislabeled. Just because you are breathing heavily doesn't mean you are doing aerobic exercise. Most aerobics classes actually receive a greater contribution from anaerobic energy systems.

Anyway, since aerobic exercises like running are low intensity by definition... how can they possibly be ideal for fat loss? They violate the theory of absolute intensity! Let's examine this in more detail.

We can objectify absolute intensity by using the intensity factors from Chapter 3 of THE Theory of Fat Loss. The relevant stand-alone intensity factors for this disucssion include strength, power, duration (or volume), and rest time.

When you look at an aerobic exercise such as running (or any other form of steady-state cardio), you see shortcomings. Let's look at running in particular.

1. Strength- For most people, running requires very little absolute strength. In fact, as somebody loses weight, even less strength is required per step. The only way to increase the intensity of running via strength is to either gain weight or throw on a weight vest. Along those same lines, a high volume of aerobic exercise in the absence of resistance training will shrink Type II muscle fibers, decreasing a person's absolute strength.

2. Power- Power output per step isn't all that great for running. The only simple way to increase power output is to run faster. The faster you run, the more contribution you get from anaerobic energy systems (which is fine, of course, especially if your goal is fat loss) and the sooner you have to stop exercising due to fatigue. The tradeoff is increased power for decreased training time.

3. Duration (or volume)- Sure, as you get better at running, you can increase the intensity by running at that same speed for a longer period of time. But seriously, there comes a point when you can't reasonably do this anymore. The other important factor to consider is catabolism. The more you train aerobically, the more your type II muscle fibers are going to atrophy and weaken. So... a lot of that weight you are shedding is potentially coming from muscle loss, not fat loss. Do you really want that?

4. Rest time- The good thing about running is that the rest time between reps is extremely low. The bad thing about it is that you can't increase your intensity anymore by decreasing rest time. The other bad news is that if you get tired, you can't really just increase your rest time between reps all that much. You usually have to stop and take a break. In a weight room, you can perform (and more importantly, you probably will perform) another exercise when you exhaust (for lack of a better term) one lift. I suppose you could take a break from running and do pushups or something like that, but who actually does that?


What I am saying is that it is wishful thinking if you believe that you can increase the absolute intensity of running (or other aerobic exercises) enough so that it can be the centerpiece of your fat loss training. Now, it MIGHT be valid as an adjunct to training (see my similar thoughts on fasted cardio)... but then again, that would require an examination of your own individual limits. Conveniently, I will address these concerns in Part 2.

Closing thoughts: Many people have lost a great deal of weight (and even fat) doing nothing other than simply running. I am by no means saying that it is impossible to lose weight running. I am merely saying that it isn't even close to an ideal method for fat loss (and it definitely isn't a good long term solution because of the diminishing returns). For more information about why running and most fat loss programs don't work, head to The Theory of Fat Loss official Facebook page and download your free fat loss special report.

Questions, comments, concerns? Leave a comment, and I'll get back to you.


  1. This is great that you've called so much attention to this for a very simple reason. So many new lifters trying to cut fat believe it is necessary to add steady state to their agenda despite hating the activity. In that way, helping them discover that not only is it not necessary, but it is disadvantageous for them to do so is paramount to their early success. Being justified in throwing away something you hate doing in working towards a goal can be very motivating!


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