A couple of random comments

As mentioned in Part 1, interval training hurts. It’s difficult and you have to be willing to push to make them effective. Put differently, if someone is not going to work sufficiently hard at interval training, then there’s really no question about intervals versus aerobics. A half-effort interval workout doesn’t accomplish any of the things that interval training is trying to accomplish; if you aren’t willing to push yourself on the intervals, you should simply do regular aerobic training.

And, as mentioned in Part 1, thousands of people have lost fat without ever doing intervals. So while intervals may be more time efficient, and may generate more fat loss for the time invested, there’s certainly no requirement to do them to get leaned out. Can they be more effective under specific conditions? Absolutely. Are they mandatory to get lean? Of course not.

Additionally, I want to point out that intervals are not a year round kind of thing, even if that’s how people are using them. Endurance athletes typically only include them for intensive periods of 3-4 weeks, or occasionally for periods of up to 8 weeks. Yet somehow general fitness exercises are trying to do intervals year round. Folks shouldn’t be dieting more than 6-8 weeks without a break in the first place, they sure as shit shouldn’t be doing intervals for more than that without a break.

This is in addition to many people taking a good idea and being idiots about it; I have heard of people performing 2 hours of intervals (20 minutes on each piece of cardio equipment) following a lower body weight workout. That’s not productive training, that’s exercise addiction. I’ve heard of people doing intervals daily (or more). Elite endurance athletes typically only perform intervals 1-2X/week, what makes you think you need more?

Finally, and I’ll come back to this below, there’s no fundamental reason that this has to be an either/or choice in the first place. Endurance athletes typically do 3-5 steady state aerobics sessions and 1-2 interval sessions per week, there’s no reason that a dieter can’t do 2 interval sessions and 2-3 aerobic sessions/week as part of their fat loss efforts. Or, depending on the specifics of their training, a maximum of 3 interval sessions and 1-2 standard aerobic sessions.

Having said that, let’s look at some different population groups and how they might decide whether intervals or aerobics (or a combination of the two) might be best.

Beginners

A beginner just starting an exercise program will be best served with low to moderate intensity aerobics. They can begin to incorporate short intervals (15-30 seconds at a slightly higher intensity) after their first 4 weeks of regular training if desired. The only exception, as mentioned above would be something called aerobic interval training which is an entire separate topic.

Basically, beginners need to break in to aerobic training the way they break into any kind of training: slowly and gradually. Someone completely out of shape simply has no business working at the kinds of intensities demanded by interval training. The risk of injury is too high, the benefits too small. Even the original interval study (by Tremblay) had a 4 week break in period prior to beginning the intervals.

Once again, after 4 weeks or more of consistent aerobic training (where consistent means at least three times/week for a minimum of 20 minutes at a moderate intensity and beginners should gradually be increasing the duration of their cardio sessions as their fitness improves), beginners can begin to use interval training to continue improving fitness or increase fat loss. When intervals are first introduced, a small number of short intervals should be performed.

I would routinely have beginners start with 30-60 seconds pushing their normal cardio pace a bit and then resting for 4-4.5 minutes. This would be done throughout the entirety of their cardio session to begin introducing them to working a little bit more intensely. Over several weeks, the length of the interval would increase as the rest interval decreased.

Intermediate exercisers already involved in heavy weight training

This is where it gets more complicated because there are so many different ways that people might be training. As mentioned above, interval training is another high intensity workout and that has to be considered within the context of the overall training structure.

Local overtraining (of the legs) is a very real issue when you try to add interval training to a heavy leg training schedule. Someone who is trying to train legs twice (or more) per week and who adds intervals to that load can quickly run into problems. This applies to bodybuilders, powerlifters, and any other athlete who has to develop multiple capacities at once. There are a couple of solutions. This is why I didn’t include intervals in the Ultimate Diet 2.0; it already included 3-4 lower body workouts/week. Adding intervals would have just made overtraining a near guarantee.

The first is to cut back leg training (which should really be done on a diet anyhow, I’ll talk about training for fat loss in another newsletter) to reduce the overall training load. Basically, leg training should be moved to maintenance loads, with a reduction in volume, frequency, or both (intensity should never be reduced). If you were training legs for 6-8 sets twice/week you can cut back to 2-3 sets twice/week or perhaps 4 sets once/week and maintain leg strength (and size) for quite some time. Adding two days of intervals to your training, plus 1-2 regular aerobic sessions, works just fine (see comments below on sequencing). If leg training is cut back to once/week, or the volume performed more frequently is very low, intervals might be possible up to three times/week.

Athletes who need to lean out

This is another complicated situation because the term ‘athlete’ covers a lot of ground. Are we talking about an endurance cyclist who needs to drop some weight to be more effective on the climbs, a strength/power athlete who is cutting to make weight for a meet, a wrestler or boxer who needs to cut some fat.

The endurance athlete is probably already doing intervals and is already doing an absolute pile of long duration endurance training. Frankly, they are probably just better adding a bit more endurance work (30′ of extra low intensity stuff) to their main workouts or cutting back their calories a bit.

Strength/power athletes have to worry about any non-strength work cutting into their strength and performance. Many powerlifters, for example, perform a type of interval conditioning training involving sled dragging and this is arguably more specific to their sport. A great many of these types of athletes are also carrying a lot of body weight (whether muscle or body fat) and that makes high impact activities such as running a problem. Intervals can probably be worked in 1-2 days/week along with the addition of fairly low intensity (think brisk walking) cardio another 2-3 days/week. Overtraining and performance drop should be watched for closely.

Bodybuilders

Bodybuilders dieting, either for a contest, or to prepare for the next mass gaining phase, are somewhat separate from other athletes so I’m going to discuss them separately. Bodybuilding is, fundamentally, not a performance sport. So, strictly speaking, bodybuilders (unlike a powerlifter or olympic lifter) aren’t intensely concerned with poundage drops. However, dieting bodybuilders are concerned with muscle mass loss and this can be huge issue for naturals, especially if they are trying to reach contest shape.

Big drops in training poundages or intensity tends to cause muscle loss when you don’t have anabolics to stave it off; natural bodybuilders should be somewhat concerned of such. I would say that, contest bodybuilders, perhaps even moreso than the general public, has a tendency to overtrain on a diet. It’s not uncommon for bodybuilders to increase training frequency and volume, along with adding an absolute pile of aerobic activity (2 hours/day is not uncommon), all combined with a caloric deficit. This is, of course, illogical as hell: why would you add more training during the one time period you can’t adapt to it. Is it any wonder that natural bodybuilders overtrain and lose so much muscle trying to diet down?

To a great degree, I’d approach the choice of intervals versus aerobics for a bodybuilder similar to that of anybody else, even if I know most won’t listen to me: they should reduce their weight training volume and/or frequency during dieting. Intensity, in terms of weight on the bar should not be reduced. Basically they should do a handful of heavy sets to maintain muscle mass; if they simply must do more work, they can do some high rep short rest work akin to the depletion workouts in the Ultimate Diet 2.0 or something similar. There are a lot of metabolic type weight workouts (whether bodyweight, weight or kettlebell based) floating around.

To this, intervals can be added two to three times/week maximum with low to moderate intensity aerobic activity being performed several more times per week.

Sequencing training

Ok, I guess I could have really summed up the above by simply saying that beginners should stick with plain old aerobics and everybody else will need to either

1. Cut back their leg training to incorporate intervals
2. Just stick with regular aerobic training

In any event, I want to talk a bit about how to sequence intervals with weight training. I’m going to assume that the person in question is training lower body twice/week, doing intervals twice per week and doing aerobics on 2-3 other days. That would at least be close to an ideal situation under most circumstances.

There are basically two ways to go about it. The first is to do the interval workouts on non-leg training days. The advantage to this is that you get to be fresher for all of the workouts, since they are all being done rested. The disadvantage is that the chances of overtraining are higher because legs are being trained intensely 4 days/week. That is, if you do interval training 2X/week and train legs 2X/week on separate days, your legs are getting hit hard 4 days/week. This can be too much.

My preferred method is to do the interval training on the same days as your leg training. Preferably the workouts would be split up (i.e. intervals in the morning, weights in the evening, or vice versa) but that isn’t always possible. Intervals can be done after lower body lifting but I’d highly recommend staying away from anything that requires coordination. Trying to run sprints after heavy leg training is an excellent way to blow out your knee or turn an ankle; doing intervals before lifting just makes your lifting inefficient. You wouldn’t want to exhaust yourself with interval training before weights either, another excellent way to get hurt.

So let’s say we have an individual using a 4 day/week upper/lower split routine who wants to do 2 days of intervals and 2 days of aerobic training. Here’s how I would suggest sequencing it.

• Monday AM: Intervals PM: Lower body weights
• Tuesday AM: Aerobics PM: Upper body weights
• Wednesday: Off (brisk walking would be allowed for active recovery)
• Thursday: AM: Intervals PM: Lower body weights
• Friday: AM: Aerobics PM: Upper body weights
• Saturday Off (brisk walking would be allowed for active recovery)
• Sunday: Completely off (everyone should take at least one day off per week).

Nevermind that, over the decades, bodybuilders have gotten into contest shape with (often endless amounts of) cardio, runners, cyclists and swimmers are extremely lean, etc. Somehow, aerobic training has gotten a bad rap.

I think what happened is that for about 2 decades, aerobic training has been (over) emphasized over all other kinds of activity. As well, people got the absolutely wrong idea about how to use it for fat loss so you have people trotting along on the treadmill at an intensity that is just slightly higher than sitting on the couch, burning a couple of hundred calories in an hour and wondering whey they aren’t losing fat.

So folks, usually with a heavy resistance training bias or background, overreacted. And the backlash began. Basically, people get a little over-enthusiastic about a certain type of training (or eating), take it to some absurd extreme, get into problems, find an alternative and decide that the first type of training is useless, overrated, etc, etc, blah, blah, blah and they jump to the opposite extreme. They jump from one extreme to the other until, hopefully, they come back to some happy medium.

Well, I’m a happy medium kind of guy and I try to avoid that kind of binary either/or thinking; I find it more useful to examine training tools in terms of their pros and cons, benefits and disadvantages. So let’s examine both steady state aerobics and interval training for fat loss (endurance performance is a separate topic) in that fashion. In part 1, I’m going to define some terms and examine both types of activity; in part 2 (two weeks from now), I’ll talk about how to decide which is best depending on the specifics of the situation

Some definitions

Steady state training: Any form of aerobic/cardiovascular training where some reasonably steady intensity is maintained for an extended period. So this might be something akin to 20-60 minutes at a steady heart rate of 140-150 (could be higher, could be lower). I’m just going to call this cardio or aerobics, even though I know some people get into longwinded semantic arguments about it. I’m sure everybody knows what I’m talking about.

Interval training: Essentially any form of activity that alternates higher intensity activity (such as 30-60 seconds almost all out) with periods of lower intensity activity. The rest interval can be passive (sit on your butt) or active (keep moving at a low intensity). While weight training can technically be considered interval training, I’m going to restrict this article to interval training done with standard cardio modes (i.e. running, cycling, stairmaster, etc). A typical interval workout for fat loss might be a short warmup followed by 5 repeats of 60 seconds near maximum intensity alternated with 60-90 seconds of very low intensity activity, followed by a 5′ cool down. This is often referred to as high intensity interval training (HIIT) which differentiates it from aerobic interval training discussed immediately below.

Aerobic interval training: For completeness, I want to mention a third, sort of hybrid, form of training that is usually referred to as aerobic interval training. This is a type of training often used by very untrained beginners who are simply unable to perform 20 minutes or more of continuous aerobic activity. So they might perform 5 minutes of low intensity aerobic activity prior to taking a short break, followed by another 5 minutes of low intensity aerobic training, until they accumulated 20-30 minutes of activity. Over their first several weeks of training, they would try to increase the duration of each aerobic interval session while decreasing the rest interval. Additionally, many strength and power athletes do a type of aerobic interval training usually referred to as extensive tempo running: this is a low intensity type of aerobic interval training done in short bouts. So a sprinter might run 10 repeats of 200 meters but at a very low intensity (aerobic intensity) with 100 meters of walking in-between. In this article, I’m not talking about aerobic interval training when I compare and contrast traditional aerobic training and interval training; aerobic interval training is sort of a third category that doesn’t apply to this discussion.

Moving on

Ok, so now that we’re on the same page definition wise, I want to compare and contrast aerobic and interval training in terms of potential pros and cons. This will allow us, in part 2 (two weeks from now) to look at how to integrate the different types of training into real world workout schemes.

Steady state aerobics: Pros

1. Depending on the intensity, steady state aerobics tends to burn more calories during the exercise bout than interval training.
2. More appropriate for beginners.
3. Can be done more frequently, daily or more often (if desired) although this depends on the duration, intensity and frequency as well as the setup of the rest of the training program.
4. Some research finds suggests that regular exercise helps people stick to their diet better. In that interval training can’t (well, shouldn’t) be performed daily, low intensity activity may help people stay on their diets.

Steady State Aerobics: Cons

1. Most indoor aerobics modes tend to be boring, especially for long durations. Exercise can, of course, be done outdoors but this raises a whole separate set of issues (bicycle safety, running outdoors, traffic, etc) that are beyond the scope of this article. This is a big part of why gyms have music and televisions; I have seen one with a cardio movie theater.
2. An excess of endurance training, especially at higher intensities (too close to lactate threshold, a topic for another newsletter) seems to cause muscle loss, decrease strength and power, and cause overtraining. This is major issue for bodybuilders and strength/power athletes but can be avoided by keeping the intensity under control.
3. Too much repetition of the same mode of aerobics can generate overuse injuries, both runners and cyclists are prone to knee problems, swimming causes rotator cuff issues (and the cold water tends to increase hunger), etc. This can be avoided by non-endurance athletes by rotating the type of activity being done.
4. Unless people are tremendously aerobically fit, it can be difficult to burn a huge number of calories unless the duration of each workout is just ridiculous. So, at moderate intensities, the average person might burn 5-10 calories/minute; a 145 lb person burns about 100 calories per mile walking or running. So over an hour aerobic session, you might achieve 300-600 calories burn. While this can certainly add up if done daily, it’s still a fairly small expenditure. The people trotting along on the treadmill or spinning on the bike at low intensities, often for only 30 minutes, are burning jack all calories. Which are usually more than compensated when that person figures that they must be burning at least 1000 calories and rationalizes that cheeseburger and milkshake because of it. This is one of those weird ironies: very high caloric expenditures through aerobics are reserved for trained endurance athletes, and they typically don’t need it. The people who need to be burning a lot of calories through aerobic activity usually aren’t able to, at least not initially.

Before continuing, I should probably bring up one of the more idiotic arguments against steady state aerobics here. The argument goes something along the lines of “Aerobic training is useless because, as you adapt and become more efficient, the same workout that burned a significant amount of calories over 40 minutes takes 60 minutes because you’re getting more efficient.” This is about as logical as saying that weight training is ineffective because the same weight that was difficult for 12 repetitions is now too light, and you have to do more repetitions with it. Except that, in the case of weight training, the suggestion would be to add weight to the bar.

And the same exact thing can be done with aerobic training: as the body adapts (and you become fitter), you can increase your caloric expenditure by increasing the intesity of your workout. So say that you were doing the stairmaster at level 8 and a heart rate of 140 beats per minute for 40 minutes. Now you’ve adapted and level 8 is only a heart rate of 130. Well, you could go to an hour, or you could increase the intensity to level 9 and burn more calories during those same 40 minutes. In addition, exercise efficiency doesn’t vary that much; in cycling for example, it varies between about 20-25%. So even if you increase your efficiency by 5%, this would only change the caloric expenditure for a given exercise bout by that same 5%. A 400 calorie workout becomes a 380 calorie workout. This is hardly a change worth decrying steady state aerobics before.

Interval training: Pros

1. For a given time investment, interval training leads to a greater fat loss and this occurs despite a smaller calorie burn during activity. This is because interval training generates a much larger EPOC (excess post-exercise oxygen consumption) which are the calories burned post exercise.
2. Interval training may improve the muscle’s ability to use fat for fuel more effectively than aerobic training (note: recent studies have also suggested that interval training can generate very rapid improvements in endurance performance in a very short period but this is beyond the scope of this article).
3. Time efficient: Not everybody has the time to devote to an hour (or more) of aerobic training per day. A properly set up interval workout may only take 15-20 minutes.
4. Time seems to pass faster: Compared to regular aerobics, which can be mind numbingly dull (especially if done indoors), the change in intensity with intervals seems to make the workout pass faster.

Interval Training: Cons

1. The intensity of intervals makes them inappropriate for beginners. One exception is a style of training called aerobic intervals which I mentioned above. But high intensity interval training is simply inappropriate for beginning exercisers, for the same reason that high intensity weight training is inappropriate.
2. Intervals are high intensity training, this has implications for the overall training setup (discussed in more detail in part 2) and integration with the rest of your program (i.e. weight training). Simply put: if you think you can train legs in the weight room 2-3X/week and do intervals an additional 2-3X/week on alternate days, you are incorrect unless you are deliberately trying to overtrain or get injured.
3. Higher risk of injuries: this depends somewhat on the type of activity with high impact activities such as sprinting carrying a higher injury risk (especially for heavier individuals) than intervals done on the bike or Stairmaster.
4. Limited in how many days they can be performed. Two to three days per week is about the maximu for interval training, most endurance athletes won’t do intervals more than twice/week. Have I heard of people trying to interval daily? Yes. Do I think it’s a good idea? No.
5. Intervals hurt, especially intervals in the 60-90 second range where muscular acid levels are very high. If you’re not willing to push yourself, you won’t get much out of interval training. You know the warnings on most aerobics machines, that tell you to stop if you feel signs of exhaustion or fatigue; that’s what a properly done interval program should feel like. Sensations of burning in your legs (from high acid levels in the muscle) along with extreme discomfort are not only common but expected. Some people also report nausea initially, this can be made worse if they have eaten too close to training.

To be continued in Steady State and Interval Training: Part 2.

"Most of them tell people to do the intervals after the weights, so what kind of energy to they have left to do any hard intervals? Not much. But, if they said to do 30 minutes of cardio, how slow would they pedal? Pretty damn slow.I’m torn between thinking that they (the trainers) are outright wrong, and thinking that they know you’re right, and just choose to allow the trainee to believe that this is the best way because it drives them to work harder. I don’t think the average fat loss client works out all that hard with the weights, anyway. They are often newbies to weights and simply don’t know what they are capable of, so they go low. They do steady state cardio at a pretty low intensity, too. Intervals might be the only thing they do with any intensity. They KNOW intervals should be “brutal,” but since they only last 20-30 seconds each, they do them."

Ok, let’s look at this since it is a good point. First off, I’d note that in the article Steady State vs. Intervals: Explaining the Disconnect Part 2, I specifically mentioned ‘making people work hard for a damn change’ as one reason that intervals might be generating superior results in the real world. No doubt, getting the average trainee who thinks they are working hard but really aren’t to go actually put out some intensity for a change is a good thing. Tangentially: a lot of why a many systems of diet or training ‘work’ is because, at the end of the day, most non-idiotic approaches to diet or training will ‘work’. A lot of it is convincing the reader/trainee/dieter that the system is valid because, if they believe in them, they will follow them. And as long as the program isn’t truly ridiculous, it will then ‘work’. So, assuredly, if someone has been convinced that intervals are ‘superior’ by silly rhetoric and bad science and that causes them to actually work their balls off for a change, that will be of some benefit. At least until they blow up from too much high-intensity training for too long on too few calories. Then they’ll end up on my forum asking how to ‘fix a broken metabolism’ or seeking out ‘adrenal fatigue’ supplements but I digres….. However, if you’re actually talking about a total newbie who is pansying around in the weight room, I’m not sure about the realities of them going and truly pushing hard on intervals. They may think they are but, the reality will likely be far different (in the same way they think they are working hard in the weight room and really aren’t). I just don’t see the average newbie willing to push themselves that hard. Which is, of course, a point I made in the article Steady State and Interval Training Part 1. As con #5 of intervals, I specifically listed

"Intervals hurt, especially intervals in the 60-90 second range where muscular acid levels are very high. If you’re not willing to push yourself, you won’t get much out of interval training."

I simply find it hard to believe that a beginner who isn’t working hard in the weight room is going to magically start working hard on intervals just because they are short. Again, I’m sure they think they are but the intensity required to make intervals productive or worthwhile is very high. And the required intensity actually goes UP as the duration of the interval goes DOWN. I guess, after nearly 20 years of observing trainees in commercial gyms, I find it unlikely that:

• A beginner is going to generate that level of intensity without a trainer or researcher standing there screaming at them to push
• Someone who has trashed themselves in the weight room is going to have the energy to put much into intervals unless they drastically cut their weight volume back (and note that the interval guys are usually pushing intervals AFTER fatiguing metabolic weight training). And this was sort of the point I made in part 2 of the article on the main site along with last week’s blog posts: when trying to incorporate interval training into a training program, something else has to be cut back, reduced or even removed.

But that’s not what I see being recommended or advocated. People are being told to work harder, more often, WHILE cutting calories and carbs. Whether they are or not is probably debatable; for every person I see blasting themselves daily with intervals on top of too much weight training and just trashing themselves, there are probably 10 more who are just going through the motions and wondering why they haven’t become a FAT BURNING FURNACE (TM). The whole point of intervals is the intensity used (duration of course plays a role but intensity is the more major factor). If you can’t go hard (either b/c you’re a newbie and don’t know how, or your tired from previous training), I would argue that it will have LESS benefit than a half-hour (or whatever) of proper steady state. Ten to fifteen minutes of half-effort intervals won’t burn many calories during the bout, you sure won’t get any HUGE EPOC benefit so all you’ve done is convinced yourself that you’ve done more than you have. I just don’t think you can have it both ways. You can’t argue in one breath that intervals are superior because of the intensity and then argue that noobs or tired trainees are going to get a benefit doing it more often (or after an excessive weight workout) if they aren’t actually able to go hard in the first place.

A secondary focus has been on what I’m seeing people do in practice as they have been convinced (wrongly) that intervals are the only way to train.

At the same time, I want to make it absolutely clear that I am not anti-interval. They are a useful tool and have their pros (and cons). It’s the uncritical belief that they are either the only or the best way to train (and the arguments used to support such) that I have a big problem with. Or the idea that they are the only type of training that can or should be done.

As a quick introduction, Steady State and Interval Training: Part 1 would be a good place to start for an analysis of what the pros and cons of steady state and interval training are.

Now, I’ll be the first to admit that I am a wordy bastard, which is why I’ve been going on about this for a month. I also had a lot to get off my chest because the terrible advice and spurious arguments being made by the pro-interval camp piss me off.

But since some of you may be tuning in for the first time and/or you simply didn’t or don’t want to read the endless verbiage in the blog, I thought I’d do a quick summary to each of the articles I wrote along with a link to an article that sums up my recommendations to people.

After a brief introduction to the topic, the first thing I looked at was a research review on Endurance Training and Obesity: Effect on Substrate Metabolism and Insulin Sensitivity which looked at improvements in fat oxidation and insulin sensitivity for steady state versus interval training. Short summary: the steady state cardio showed a beneficial adaptation in both fat oxidation and insulin sensitivity that the interval training program did not.

Pole Vaulting for a Hot Body had to do with the commonly stated argument that you can run a marathon and still be fat but 400m runners are always lean, ergo interval training is superior for fat loss. There are several problems with this argument not the least of which that 400m runners do most of their work at low intensities and the high intensity sprint work they do is nothing like the type of interval training that is being advocated for fat loss in the first place.

In a continuation of that idea, I pointed out that the people making this argument are essentially comparing recreational runners to high-performance sprinters, which makes no sense. In Sprinters vs. Marathoners, I pointed out that ELITE marathon runners are always lean. It’s just a ridiculous argument all around and comparing recreational joggers to elite athletes is intellectually dishonest in the first place.

Another argument that the superiority of interval training rests on is that it generates an exceptionally large post-workout calorie burn. In the research review Effects of Exercise Intensity and Duration on the Excess Post-exercise Oxygen Consumption, I put this idea to rest. While the relative burn following high-intensity training may be larger, the total absolute contribution is still miniscule (partly because the total calorie burn of the average interval sessions is pretty small, even a larger PERCENTAGE burn doesn’t amount to much). In one study, following intervals, a whopping 35 some odd extra calories were burned. Yippee.

There is also the simple fact that, almost no matter how you cut it, the total calorie burn during a longer steady state bout will be in excess of whatever occurs from interval training. In the article Steady State vs. Interval Training and EPOC: Practical Application, I compared interval workouts to steady state workouts from my own training (calorie values based on numbers taken from my Powermeter equipped bike, a Bodybugg and my new Polar watch that estimates calorie burn). This is in addition to the fact that, for the same or lesser calorie burn, intervals are MUCH harder and interval training can’t be done daily. And since most trainees train more than a handful of time per week, this is a problem.

Now, while most of the arguments that intervals are typically based on appear to be bogus, there is the simple fact that, for many people, they seem to be more effective for fat loss (at least under certain circumstances). I examined this apparent disconnect between the research and the real-world in the next two blog pieces.

In Steady state vs. Interval Training: Explaining the Disconnect Part 1, I examined the now infamous Tremblay interval study and offered the potential of muscle gain (only relevant for beginners who aren’t lifting) and increased fat oxidation as potential mechanisms for increased fat loss. I’d point out again that that study only showed a fairly small total fat loss in the first place, certainly nothing to write home about.

In Steady state vs. Interval Training: Explaining the Disconnect Part 2, I examined the potential of the hormonal response, blunted appetite (probably the real reason intervals show up as superior in studies with no diet control), and the simple fact that believing in intervals may get people training hard for a damn change. The simple fact is that, given that most people train like wimps, if you get them to work harder for a change, good things usually happen.

In an article on Exercise Efficiency, I examined yet another commonly held belief about steady state exercise, that efficiency improves drastically, reducing calorie burn. Simply, this is dead wrong, changes in efficiency take years of grinding effort (Lance Armstrong improved his efficiency by 1 percent per year and it took him 3-6 hours per day on the bike to do it) and only exert small effects on calorie burn anyhow. Of course there is the simple fact that, even if folks are getting more efficient during steady state, the workload can simply be increased during exercise to counteract this.

In a research review, I examined Metabolic Adaptations to Short-term High-intensity Interval Training, looking at the adaptations to short-term interval training. That paper made it clear that, at least in untrained individuals, fairly low volumes of high intensity training can induce adaptations similar to much longer duration steady state programs. While intriguing to be sure, there is the simple fact that this training was being done in isolation, there is also the question of whether beginners can even sustain the intensities or durations of interval training, along with the question of what happens after the first 2-6 weeks and whether or not the adaptations keep occurring (I’d note here that studies in trained endurance athletes show that interval training stops having much of an effect after about three weeks).

In Steady State vs. Interval Training: Summing Up Part 1, I made the point that all of the interval training studies or what have you have always been done in isolation. No hardcore fat loss or low-carb diet, no weight training, just intervals. I raised the question of why people are uncritically assuming that interval training three days per week can simply be added to the rest of training (or diet) without looking at the program as a whole. Because this is really at the core of the problems I’m seeing. People are taking isolated aspects of training and throwing them together without consideration of the whole effect.

In Steady State vs. Interval Training: Summing Up Part 2, I examined the three ‘prongs’ of current fat loss methodology that I currently see being abused. Those are very low-carb diets, interval training and metabolic weight training. Folks seem intent on not only taking the research on each individual component out of context but throwing it together in the training blender and hoping it sticks. And that’s before trainees, brainwashed by the silly idea that only intervals are effective decide to train more than three times per week. Folks are trying to do intervals 3-5 times per week with full body weight training several times per week while eating zero carbohydrates. And they are getting destroyed.

And finally that brings me to today where I can wrap up this series and move on to other things. As it turns out, I had already addressed this issue in some detail the article Steady State and Interval Training: Part 2. It basically summarizes what I think about how to best incorporate both interval and steady state training into a proper program for different athletes and folks of different training status (e.g. beginners, intermediates, athletes, bodybuilders, etc).

This is also a topic that I look at in some detail in the new Stubborn Fat Solution book because. Two of the protocols use intevals for very specific reasons so I had to address how to integrate them with other aspects of training so that dieters wouldn’t nuke themselves.

So that’s it, about a month of constant commentary. I’m sure I pissed some people off. Especially those for whom selling intervals to the masses is their bottom line. Something tells me I won’t get invited to the inner circle parties anymore. Hopefully I made some folks think about the advice they’re giving or taking or how they are training on a day-in, day-out basis.

But just in case, nobody has paid attention to a word of this, or simply missed the point, I’d sum up most of this by asking the following question:

If the typical high level athlete typically only performs, on average, two very high-intensity days of training per week, what makes the general trainee (seeking fat loss or whatever) think that they can or should do more?

More importantly, what makes the gurus, with all of their supposed years in the trenches training people, think it’s a good idea or something that that they should recommend in the first place?

***

In Steady State vs. interval training: Summing up Part 1, I started to put together some of the information I’m blogging about by making a point about the types of problems I’m seeing in practice with the pro-interval myopia. Simply: given that a majority of trainees train more frequently than 3X/week, once they have been convinced that intervals are the only way to train, problems start. They end up trying to do intervals at every session, in addition to a heavy weight training load for the legs and they blow up.

But thats’ not the only problem I’m seeing and, today, I want to take another side-trip to look at the three distinct parts of what is currently being given to trainees in terms of how they should be training.

In a recent commercial fat loss product I listened to (yes, I have to read everything, even the stuff I know will be garbage) pretty much every interviewee’s answers can be summed up as

• Intervals are best for fat loss
• Metabolic weight training is the best for fat loss
• Low-carb diets are best for fat loss

With the standard spurious arguments given for each.

What’s going on here, why are these three things coming up again and again and what’s the problem with what’s being recommended?

Simply, the problem I see is that people are taking a number of isolated data points (e.g. individual studies looking at only one thing) and assuming that, if they put all of those concepts together, thing will work even better. This is even assuming that the study results in question are actually saying what people say they are saying. Let me look at that quickly first.

For example, the superiority of intervals is usually based on the supposed afterburn/EPOC, an idea that research into EPOC shows is irrelevant. And even looking at the (non-diet controlled) studies comparing intervals to steady state, the results are hardly anything to write home about. Half a kilogram more fat over 20 weeks, a pound over 12 weeks, whatever. Yeah, you’ll be ripped by 2032 at that rate. Do intervals have advantages over steady state in some ways? Yes. But steady state has its own set of advantages (not the least of which that it can be done daily which interval can’t, or rather shouldn’t).

Both are simply tools with their own sets of pros and cons.

The one study suggesting a massive caloric expenditure from metabolic weight training has never been replicated and, while metabolic weight training may have other advantages (such as glycogen depletion, etc.) it also has limitations (not the least of which is that it’s an inferior way to maintain muscle mass on a diet). To say that metabolic weight training is de-facto superior is simplistically dumb and completely incorrect. All types of weight training are simply tools with their own sets of pros and cons and should be used accordingly.

I don’t want to get into detail on the lowcarb thing just yet, that could be another entire series of blog posts, especially with the low-carb retards coming out of the woodworks after the publication of Gary Taube’s book “Good calories, Bad Calories” (I’ll do a detailed review when I get a chance). Sufficed to say that while low-carb diets may have their advantages, they aren’t magic. At least one study have suggested exactly zero advantage over lowered carbohydrate but non-ketogenic diet when calories are controlled. Low-carb diets are simply one tool with its own sets of pros and cons.

The studies that low-carb advocates always like to cite are invariably not calorie controlled. And while the subjects may report that they are eating the same amount, this is unlikely to be the case. If low-carb diets have an advantage, it’s that most people spontaneously eat less. The only metabolic advantage is that, people on lowcarb diets are eating less calories.

But for the sake of argument, let’s just assume that all three of the statements above are actually true, at least when studied in isolation. Let’s assume that intervals are superior to steady state, that metabolic weight training is best for fat loss and low-carb diets are superior for fat loss. At least by themselves.

What happens when you throw them all together?

In this case, some bad things. Because while glycogen depletion can improve fat loss (a point I made over 10 years ago in The Ketogenic Diet and used for a specific goal in the Ultimate Diet 2.0, even if everybody is only now jumping on that bandwagon), the simple fact is that high-intensity training can NOT be sustained in the long-term without dietary carbohydrate. Eventually glycogen gets depleted, performance falls off and folks overtrain.

Yet now we have people trying to remove all carbohydrates from their diet, while doing glycogen depleting metabolic weight training while trying to add glycogen depleting interval work three or more times per day. Because we have a bunch of gurus who took several isolated data points (of potentially limited validity in the first place), threw them in the training program blender and vomited out some real stupidity.

And that’s where the problem is coming in. It’s a training load that almost nobody could survive with adequate dietary carbohydrates (recall, as I’ve mentioned previously and the link at the front of this blog post clearly shows, most athletes don’t do intervals more than twice per week yet the average trainee thinks that doing them every day is a good idea) and folks are trying to maintain that for weeks on end without any carbs.

Which isn’t to say that elements of each of the above data points can’t be used, just that they need to be applied and properly.

Does metabolic weight training have its role? Absolutely. I used depletion work at the start of the UD2 cycle to deplete glycogen and improve fat oxidation and offered it as a possible way of generating a certain hormonal response in the Stubborn Fat Solution for Protocols 3 and 4.

Obviously intervals have their place for both fat loss and performance and they are used as part of two of the four protocols in the Stubborn Fat Solution and can be used during other diets for various reasons. The main point, and the thing that it’s time for people to realize is that interval training:

• Can’t be done every damn day
• Can’t be done forever without a break

And, of course low-carbohydrate diets have their place (my first book was a 300 page treatise on the technical aspects of low-carbohydrate diets so clearly I feel that they have their place). Again, the first 4 days of the UD2 cycle is low-carbs (prior to a three day very high-carb refeed), and one of the four protocols in the Stubborn Fat Solution is based around the fact that chronic low-carbohydrate diets can help mobilize stubborn body fat.

But that doesn’t mean that low-carb diets are magically de facto superior for fat loss or anything else. Especially if people want or need to perform a good bit of high-intensity training. Carbs will be required in that situation, whether they are consumed daily or during some type of cyclical diet is less relevant than the fact that they will be required at some point.

Essentially, if you want to completely remove carbs from your diet, the amount of high-intensity training of any sort will have to be reduced. And if you want to do a lot of high-intensity training, you will need carbs in your diet. Either diet determines the training or training determines the diet. But trying to do both often causes major problems.

Are you getting my point here? Not only have people completely lost their minds with the pro-interval rhetoric (developing training loads that no athlete would consider doing), it ends up being combined with two other variables that end up making the problem worse.

The body can only handle so much heavy training, which is why most of the training that most athletes do is low-intensity. Yet we have a situation, and I know I sound like a fucking broken record, where people are trying to sustain training loads that are simply inhuman in the first place. They want to add too many interval sessions to too much heavy weight training AND do it under conditions of both severe carbohydrate and caloric restriction.

And, at long last, the series finishes with Steady State vs. Interval Training: A Conclusion

Summing up briefly, it showed quite clearly that, at least in relatively untrained individuals, a short-term (2-6 week) program of high-intensity interval training (workouts typically done three times per week) can generate similar adaptations to longer duration training.

In that post, I finished by asking the following questions:

There’s no doubt (and I haven’t intended to suggest otherwise) that high intensity interval training can have benefits. It’s time effective and may induce similar performance adaptations to longer duration traditional cardio. With regards endurance athletes, it’s clear that even short periods of low volume interval training can have rather large benefits for performance.

But with most of the benefits seeming to occur with only a handful of sessions per week (2-3 is the norm) and with benefits appearing to end fairly quickly (3-6 weeks), we might ask what a trainee should do when either

1. They need to train more frequently than that
2. They are looking at their training over a period longer than a few weeks. That is, if interval training stops providing benefits after 3-6 weeks, what should a trainee do for the remaining 46-49 weeks out of the year?

There is also the issue of how intervals integrate with training when OTHER TYPES OF TRAINING (e.g. weight training) are being done. That is, what happens if someone is training their legs heavily in the weight room twice/week. How realistic is it to then add high intensity interval training to that workload?

As well, what happens when someone (e.g. an athlete or obsessive exerciser) is trying to train daily? What happens then in terms of how they structure their week? If you take much of the current guru-speak (e.g. intervals are the only beneficial way to train) at face value, you end up developing a training week that no human being can survive.

And that’s where I want to start today since this will let me start to put everything together to close out this particular blog post series.

To my knowledge, pretty much every study done comparing interval training to steady state (in terms of fat loss or metabolic adaptation) has done it in isolation. The subjects were neither dieting nor doing any other form of training.

Such as weight training.

As well, the frequencies were strictly controlled in those studies. In the performance studies, typically endurance athletes replaced a small portion of their total volume (15%) with intervals. Generally 6 sessions over 3 weeks (or 2 per week) were done. In the paper I reviewed Friday, the subjects did three interval sessions per week and nothing else. Again, that’s true of most of these studies. Oh yeah, the subjects weren’t dieting, of course.

Even in the now famous Tabata study, where the subjects were doing the four minute workout four days per week (the fifth day was a partial Tabata protocol with some steady state training), that’s all they were doing. They weren’t lifting, they weren’t doing any other kind of training, just going through hell on the bike.

So why are all the gurus assuming, uncritically, that interval training can simply be ‘tacked-on’ to a heavy weight training workout without problems? Or added to a calorie restricted diet without any problems? Why are trainees assuming the same thing?

Because, in addition to the current focus on interval training as apparently the ONLY way to train or lose fat, there has been a renewed interest in full body workouts (often of the metabolic type of training with high reps and short rests). I’ll come back to that and the diet issue in more detail on Wednesday, I want to stay focused here.

So we have people who are trying to hit legs in the weight room three times per week. Sometimes its heavy, sometimes it’s metabolic stuff, sometimes it’s a combination of the two. And then add intervals to that training load. Now, if they are smart and/or lucky, they end up ONLY training three times per week. At least that way their legs are only getting hammered (and I mean totally hammered) on those three days.

And, you know…whatever. I guess if someone only has three hours to train per week and can’t fit in any more training, they might as well blow themselves out every day and just go hard. Of course, this still doesn’t address what happens when intervals stop working at the 6 week mark (as they very well might) but, again, whatever.

If you have three sessions of an hour per week and that’s all you can train, you might as well make it as time efficient as possible. Do metabolic weight room stuff for 25 minutes, intervals for 20 minutes and that leaves 15 for warm-ups and cool-downs. As long as the other four days per week are completely off, this might be workable. For a while anyhow.

And you know, if the various ‘HIIT plus metabolic weight training for the win’ gurus would make the above very clear, I wouldn’t have much of a problem with what’s being said. I still think it will eventually burn people out and that periodizing the type of training done will work better but that’s an argument nobody wins so I’m not going to bother with it.

I would also note that nobody can say if the adaptation benefits to HIIT continues past 6 weeks in beginners. It’s clear that it more or less stops after three weeks in trained folks (even in the much talked about Tabata study, the major benefits happened by week 3 with only small further benefits at week 6).

But recall my question from above, what happens when athletes (or dieters), want to train more than three days per week. Because they usually do. Can they simply do more and more and more intervals (or complexes or whatever)? The answer, as you might guess, is no.

And that’s where I’m seeing real problems. I’m seeing people, having been convinced by spurious logic (bordering on outright bullshit) that ONLY intervals are productive training or useful for fat loss, that magically steady state can MAKE YOU FATTER, trying to do nothing but interval training.

Added to three full body workouts per week.

While restricting both calories and carbs.

This is absurd.  This is beyond absurd.

A quick tangent: Wanna know what I think about ‘adrenal fatigue’? I think that in 99% of cases, it’s simply overtraining being brought on by people following the idiotic training advice being currently given. If these people would simply stop training in such a retarded fashion, the current fad of ‘adrenal fatigue’ would simply go away in most cases. But that’s another blog for another day.

Anyhow, recall from above that high level endurance athletes typically only add interval training twice per week, replacing some of their weekly volume. And they aren’t usually weight training. The rest of their volume, about 85% of it is low intensity aerobic work.

As I discussed in Pole Vaulting for a Hot Body, 400 meter runners (who aren’t doing true ‘interval’ training anyhow) only train maximally twice per week. The rest is extensive tempo (essentially low intensity work).

Most elite powerlifters only train legs hard twice per week (and many train heavily once per week and lighter the other), the ones who train more frequently use much lower intensities (and often take drugs to support the training). And, yes, Olympic lifters usually squat daily, but a lot of it is low intensity and they take years to build up to that level (and of course, use a lot of drugs to support that level of training).

This is fairly common, most high performance athletes don’t even try to do more than two high intensity workouts per week for the legs (I’m focusing on the legs here since most interval modes use the lower body and this is the muscle group that is most commonly overtrained).

These are highly trained athletes who are usually eating plenty to support their training.

Even contest dieting bodybuilders, who are usually trotted out as the ones to emulate for fat loss typically move to a split routine with primarily low intensity cardio for maximal fat loss. Yes, some are now incorporating interval sessions such as my stubborn fat protocols but, the majority of their training is low intensity.

And that’s with a reduction in leg training frequency (one of my primary guinea pigs for the Stubborn Fat Protocol 2.0 cut his leg training back to only once per week to avoid overtraining his legs due to the intensity of the SFP2.0). And the legs often still fall apart after an endless contest diet.

Yet somehow the general public has gotten the idea that they can train legs heavy in the weight room 2-3 times/week (because full body workouts are in vogue) AND add intervals multiple times per week to that load (because ONLY interval training is productive apparently). While restricting calories and carbs. And this is being promoted in various media (books, e-books, blogs, etc) as the thing to do.

Did I mention that this was completely idiotic?

Again, don’t get me wrong, I’m not anti-intervals. Clearly they are time efficient and productive in many ways. But they are also a high intensity training session for the legs and have to be counted as such. And they have to be considered within the context of the complete program including any other types of training (whether for aesthetics or performance) and diet.

And this is what is not being done for the most part. People are simply taking isolated data points about diet or training and assuming that they can be stuck together to provide maximal results. And this is getting them into trouble.

The series continues in Steady State vs. Interval Training Summing Up Part 2

Gibala MJ, McGee SL. Metabolic adaptations to short-term high-intensity interval training: a little pain for a lot of gain? Exerc Sport Sci Rev. (2008) 36(2):58-63.

High-intensity interval training (HIT) is a potent time-efficient strategy to induce numerous metabolic adaptations usually associated with traditional endurance training. As little as six sessions of HIT over 2 wk or a total of only approximately 15 min of very intense exercise (approximately 600 kJ), can increase skeletal muscle oxidative capacity and endurance performance and alter metabolic control during aerobic-based exercise.

My Comments

It’s long been felt or argued that the only way to reach the pinnacle of endurance performance is through years of grinding effort, usually involving absolute piles of low-intensity training. To a great degree, outside of the occasional period when programs based around intensification have become popular, this has been the basic approach to endurance training.

‘Miles build champions’ is a commonly held adage and after my comments about Exercise Efficiency and how takes YEARS of training to have any real impact on it, there is probably some merit to this idea.

However, efficiency is only one of several components of performance, the other two major ones being VO2 max and lactate threshold. To a great degree, similar ideas have been held regarding the time course of changes in those components with years being expected to maximize them. But is this true?

Research going back to the 1970′s (by Hickson) had questioned that idea, at least as it pertained to things such as VO2 max. In that study, subjects performed high intensity intervals (6X5 minutes at VO2 max with a 2′ break) three days per week on a bike alternated with 40 minutes running as fast as possible on the other three. In that study, VO2 max increased linearly week to week with one subject approaching an elite (for then) VO2 max score. So clearly there is some indication that at least some aspects of endurance training can improve quite quickly.

In fact, a number of recent studies, typically using cyclists have found that substituting about 15% of the total weekly volume with high intensity intervals can improve performance significantly, by up to 5%, in a matter of weeks (interestingly the maximal effect seems to occur at the three week mark with no further benefits occurring if intervals are continued beyond that point). Clearly this points to something very beneficial going on with interval training and certain aspects of performance. It was this topic that today’s research review examined in some detail.

Their initial comments are essentially identical to mine above pointing out that, while it’s usually been thought that only long-duration endurance training could improve aerobic energy metabolism, more recent work has shown similar adaptations can be induced with a much lower volume of interval training. Interestingly, the adaptations may actually happen faster with the intervals.

The researchers rely primarily on work from their own lab where they utilize a standard interval protocol consisting of a 30 second Wingate test (30 seconds all out against a braked cycle ergometer) repeated 4-6 times with a 4 minute rest period. This workout is performed three times per week for anywhere from 2-6 weeks (the earlier work I mentioned used intervals of varying lengths twice per week for three weeks, or six total sessions). I’d note that most of the work on this lab was performed on essentially untrained college aged men and women NOT highly trained endurance athletes.

I’d note that this type of training protocol looks exactly nothing like the types of interval training being currently propagated for fat loss. Rather, the fat loss type programs are usually based on longer intervals (60-90 seconds) with relatively short rest periods (60-90 seconds); this makes it difficult to apply the research results.

The results from their work are somewhat interesting, in one, a mere two weeks of the above protocol improved exercise tolerance (the ability to sustain a given workload) by nearly double. However, there was no increase in VO2 max suggesting that the adaptations were peripheral (e.g. occurring primarily in the muscle) and not central (e.g. occurring in the body’s ability to transport oxygen via the bloodstream). The researchers note that other studies using HIIT have found an increase in VO2 max but invariably used a larger volume of training.

Looking at the cause of the adaptations, the researchers found increases in aerobically producing energy enzymes that were significant with only the short interval group. In a related study, they compared the above interval protocol to a group that performed standard steady state cardio for 90-120 minutes for the same 6 sessions. Identical results were seen in both groups but the interval group exercised only 2.5 total hours compared to 10.5 hours in the steady state group.

Additional adaptations in the interval group also include changes in carbohydrate metabolism including increased glycogen storage, reduced glycogen utilization and lactate production during exercise along with increased glucose uptake into skeletal muscle. Markers of fat oxidation were unchanged, at least over the 2 week studies (in this vein I’d refer readers back to my research review on Endurance Training and Obesity: Effect on Substrate Metabolism and Insulin Sensitivity which found that only steady state cardio increased fat oxidation rates and interval training did not).

In contrast, the review mentions another interval training paper (which used a much higher volume of training) that did show an increase in fat oxidation over only 2 weeks. The subjects in that study performed a massive 10 sets of 4 minute intervals at 90% of VO2 max, significantly more volume than the small amount used in the studies described above (and far far more than any of the popular interval programs for fat loss).

Although the paper went into some detail on the signalling mechanisms by which interval training may work, I don’t think a detailed discussion will be that valuable so I’m going to skip over it.

Jumping to the practical implications of their work, the researchers comment that the main complaint about exercise programs is a lack of time and, as such, exercise innovations that allow for similar benefits in less time are clearly of interest from a health point of view. Interval training may play a role here (I mention time efficiency as one of the ‘pros’ of interval training in the article Steady State and Interval Training: Part 1) and at least one study suggested greater long-term adherence to exercise programs requiring less time investment.

At the same time, the researchers mention explicitly that it’s unclear how longer term interval programs will work compared to more traditional training programs and there may be different times courses of adaptations for each kind of training (e.g. perhaps interval training causes more rapid initial gains which then plateau sooner).

As well, the type of interval program they use in their lab requires not only specialized equipment but, to quote them “…an extremely high level of subject motivation.” As others have pointed out, the intensities used in many interval training studies are essentially unachievable by beginners which raises many more questions such as:

Can a beginner even achieve the intensities and durations used in these studies to get the benefits

Would a modified interval training program, using less intense or lower duration intervals achieve the same benefits in the first place?

You get the idea.

Summing Up

There’s no doubt (and I haven’t intended to suggest otherwise) that high intensity interval training can have benefits. It’s time effective and may induce similar performance adaptations to longer duration traditional cardio. With regards endurance athletes, it’s clear that even short periods of low volume interval training can have rather large benefits for performance.

But with most of the benefits seeming to occur with only a handful of sessions per week (2-3 is the norm) and with benefits appearing to end fairly quickly (3-6 weeks), we might ask what a trainee should do when either

1. They need to train more frequently than that
2. They are looking at their training over a period longer than a few weeks. That is, if interval training stops providing benefits after 3-6 weeks, what should a trainee do for the remaining 46-49 weeks out of the year?

There is also the issue of how intervals integrate with training when OTHER TYPES OF TRAINING (e.g. weight training) are being done. That is, what happens if someone is training their legs heavily in the weight room twice/week. How realistic is it to then add high intensity interval training to that workload?

As well, what happens when someone (e.g. an athlete or obsessive exerciser) is trying to train daily? What happens then in terms of how they structure their week? If you take much of the current guru-speak (e.g. intervals are the only beneficial way to train) at face value, you end up developing a training week that no human being can survive.

These are critically important topics that I’ll discuss in Steady State vs. Interval Training: Summing Up Part 1

You can consider this article a sort of side-trip about the whole issue of intervals versus steady state cardio that I’ve been discussing in the previous articles. I’ve mentioned exercise efficiency briefly in a couple of posts but want to make some more detailed comments before continuing on with the series..

One of the common arguments against steady state cardio is something akin to ‘Steady state is useless because you become more efficient at it and burn less calories doing it.’

I’ve already addressed part of why this argument is stupid but want to go into a bit more detail.

The simple fact is that you get more efficient at anything you do regularly. This is true of weight training and interval training. And what do you do when that happens? You increase the workload (e.g. add weight to the bar, try to go faster in your sport, use a higher intensity for your intervals). Duh.

Yet somehow that same logic seemingly can’t be applied to steady state cardio, at least not according to gurus with an interval program to sell.

Somehow, even though you get better at it (assuming that this does significantly impact on calorie burn, which I’ll address next), you can’t ever work harder.

That is to say say I start walking at 3.5mph on a treadmill. Say that six weeks later I’ve become more efficient and am burning less calories. Are the anti-steady state people seriously suggesting that I can’t simply raise the workload to say 3.8 mph (or 3.5 mph on a 1.5% incline) to burn more calories (to offset any increase in efficiency)?

Yes, that does seem to be what they’re saying. So while it goes without saying that they would suggest adding weight to the bar when things get lighter, or increasing the intensity of intervals when they get harder, this somehow can’t be applied to steady state cardio. Can you understand why I have such a bug up my ass about this topic and the stupid arguments involved? It’s because they make absolutely zero fucking sense.

But I digress.

A bigger question is whether any of the above actually makes a shit’s worth of difference for the average trainee. That is, does efficiency really improve so drastically as to radically reduce caloric expenditure during steady state (some people seem to have this implied idea that you’ll be burning like half as many calories due to improved efficiency, or whatever)?

The short answer is no.

The long answer follows:

First I should probably define efficiency in the sense it’s being used here. The key thing to realize in looking at this is that most of the energy that you expend on any activity is lost as heat, only some percentage of it actually goes to producing actual work.

I mentioned in a previous blog post that, for cycling, this number ranges from about 20% (only 1/5th of the amount of energy you burn actually goes to power production) to 25% (1/4 of the total amount of energy burned goes to work production). Essentially efficiency is a measure of how much external work you get for a certain input of energy.

Of course, from a performance point of view, higher efficiencies are better, the more mechanical output I get for a certain amount of energy input, the faster I will go (on the bike, running, etc).

Now, the next question to look at is how much caloric expenditure (e.g. to cover a certain distance) varies for that range of efficiencies. Let’s say I ride my bike and generate a total power output of 420 kj (I’m picking this odd value to make the math simpler). To convert this to calories, I divide by 4.2 so that’s 100 calories. But only that only represents some percentage of the total I burned because only 20-25% of what I burned calorically went into the actual power output that my Power meter measured.

So to calculate it back out, I can divide by 0.2 for 20% efficiency or 0.25 for 25% efficiency. I’m going to use the extremes to save a bunch of calculations and look at what the maximum realistic change might actually be.

100 calories /0.2 = 500 calories burned

100 calories /0.25 = 400 calories burned

No doubt, I burn fewer calories if I’m more efficient, about 20% less comparing the lowest efficiency to the highest efficiency. So for every 1% increase in efficiency, I burn 4% fewer calories at the same workload.

But here’s the next question, how much training does it take for me to go from a 20% efficiency to a 25% efficiency? Or even to increase my efficiency by 1%?

The short answer is: essentially forever.

The longer answer is: ok, not exactly forever but it’s a time frame that is utterly irrelevant to the general population.

To make my point, I’m going to pull a data point from a study of arguably the most dominant cyclist to yet live: Lance Armstrong.

Tracked over approximately 7 years of training, Lance improved his efficiency by a whopping 8%. Or roughly 1% PER YEAR. And, to quote the paper directly:

“It is hypothesized that the improved muscular efficiency probably reflects changes in muscle myosin type stimulated from years of training intensely for 3-6 h on most days.”

Read that closely, three to six hours of cycling per day damn near EVERY DAY to get a 1% efficiency increase PER YEAR.

And yet, somehow, folks think that walking on the treadmill a few times per week is going to ramp up their efficiency such that they are burning massively less calories during their workouts after a few weeks.

Note: A recent controversy has erupted over the paper I cited above. There are now accusations that Coyle mis-analyzed the data; the re-intrepretation suggests that Lance actually did not improve his efficiency much at all. Which is yet another nail in the coffin of the entire argument: if Lance Armstrong, cycling 6 hours per day damn near daily for years on end isn’t becoming more efficient, someone walking on the treadmill a few times per week damn sure isn’t either.

Sorry folks, it doesn’t work that way. There’s a reason that endurance athletes train damn near daily for years on end to reach their ultimate genetic limit of performance. After VO2 max peaks and lactate threshold peaks, the only way to get better is with efficiency improvements. And it takes years of grinding effort to improve this by even a small amount.

But you say, what’s happening when, after a few weeks, it’s suddenly easier to do my workouts?

That’s not efficiency, that’s called improving fitness.

And, as above, when that happens you have to increase the workload.

When 100 lbs on the bar is too light, you go to 110 lbs.

When 200 watts during intervals is too easy, you go to 220 watts.

And when 3.5 mph on the treadmill becomes easier, you raise the speed, incline or both.

Yet every pro-interval guru who would tell you do the first and second, seem to feel that it’s impossible to do the third.

Note: For folks coming in late, let me make it clear again that I am not trying to make an argument for steady state or against interval training (as both have their roles to play), I’m simply trying to point out some of the more idiotic arguments being made by the pro-interval camp to try and discredit steady state cardio as a useful modality.

Next up, I want to look at Metabolic Adaptations to Short-Term High-Intensity Interval Training

The Hormonal Response

The hormonal response to any kind of high-intensity training is significantly different than in response to low-intensity training. While low intensity training typically only releases noradrenaline (from the nerve terminals) with only small amounts of adrenaline (from the adrenal medulla), high-intensity exercise releases both adrenaline/noradrenaline in large amounts.

For various reasons, all of which are discussed in some detail in The Stubborn Fat Solution, that hormonal response can be beneficial to fat loss. Quite in fact, in that book, I use intervals for specifically that reason in two of the stubborn fat protocols.

In addition to potentially impacting on fat mobilization (lipolysis), this hormonal response can have one other major effect that is probably a major cause of the results in many of the studies being cited by the pro-interval group. That’s that high intensity exercise often blunts hunger.

Blunted hunger/appetite

If there is a single glaring flaw in nearly all of the research that is being used either in support of intervals or to tear down steady state cardio, it’s that diet is uncontrolled. This is important for two reasons, one physiological and one practical.

The practical one should be pretty damn obvious: anybody who is trying to lose fat without paying attention to their diet has it ass-backwards (for context, one of the most rabid pro-interval gurus has ‘Correct Nutrition’ as the #1 bit of importance in his Fat-loss Heirarchy). He’s assuming that diet is fixed, and then using research that is not controlling diet at all.

The other issue is a physiological one, having to do with how exercise can impact on appetite. Now, this could be an entire blog post (or series in its own right) as there are myriad physiological and psychological ways that training can impact on appetite (sometimes exercise decreases hunger, sometimes it increases it).

However, at least one data point shows rather clearly that high intensity activity tends to blunt hunger more than low-intensity activity.

Quite in fact, in one of the studies currently being used to claim that ‘Steady state cardio makes you fatter’ (the steady state group had a 0.5 kg fat gain in visceral fat compared to a 0.5 kg fat loss in the interval group), the researchers explicitly state:

“However, our estimates of energy expenditure and intake lack sufficient precision to comfortably conclude that energy balance was unaffected in the HIIE condition. Thus, it is feasible that the change in FM that occurred in HIIE may have been influenced by unreported changes in diet. Indeed, HIIE- induced suppressed diet intake may be one of a number of possible factors underlying the fat loss effect of HIIE.11 For example, HIIE may have suppressed appetite or decreased attraction for energy-dense foods.24,25.”

Meaning that the interval group may have lost fat because the exercise may have made them eat less.

While a huge benefit if someone isn’t controlling calories has no real relevance if they are. I’d also note that the total fat loss in that specific study wasn’t much, a whopping 1.5 kg (3.3 lbs) over 15 weeks. The Rapid Fat Loss Handbook can take that much fat off of a person in ONE WEEK.

Tangential question with a tone that moves beyond snarky and to outright accusation: how come the pro-interval gurus who trot out these studies don’t ever mention these specifics when they claim that intervals are superior to steady state cardio? That the intervals may have simple worked because subjects ate less, or that the actual real-world fat loss amounted to jack shit in the first place?

Making People Work Harder for a Damn Change

Ok, this one isn’t addressed in the research but it’s still important to results.

Let’s face facts, most people train like wimps. I don’t care how hard they claim to work, I’ve spent damn near 20 years in commercial gyms and the simple fact is that most don’t.

Go look at the average person on the treadmill, odds are they aren’t even breaking a sweat or doing anything beyond watching tv and talking on their cell phone. And while my comparison on Saturday was intervals to a moderate aerobic sessions (where I can easily burn 10 cal/min), the average person may be burning closer to 5 cal/min during ‘fat-burning’ cardio. Or 150 calories over a 30 minute pissant steady state session. Under those conditions, a 20 minute interval session (which may burn 200+ calories) actually does win out from a simple energy balance perspective, in addition to any other benefits discussed above.

If there’s one thing that the whole interval training fad has done, it’s to get people to actually work somewhat out of their comfort zone. But to a great degree, this has less to do with steady state cardio as a modality and more about how it’s used. Fine, people usually do steady state cardio at irrelevant intensities. No argument here. But that has nothing to do with steady state and more to do with the fact that people are

• Being given shitty advice (fat burning zone, bro)
• Lazy

So, yes, if telling them that intervals is going to MELT THE FAT OFF OF THEM actually gets them to work hard, that’s a benefit. I’d also note in this context that this can backfire. People who are too wimpy to suffer aren’t going to do intervals effectively and will probably end up getting LESS out of an interval workout (that they half-ass) than a properly done steady state cardio session (which they’ll also half-ass).

And of course none of this really gets back to the question I posed on Saturday regarding how often I can or should do intervals compared to how often I can or should do steady state. Which is what my next article will discuss.

Now let’s take a quick look at the topic of Exercise Efficiency

With any realistic amount of intervals, not only does the total calorie burn of the workout itself pale compared to longer moderate intensity steady state sessions, the EPOC simply doesn’t amount to anything. Certainly not enough to explain the rather rabid and myopic recommendation of that form of training.

Yet we seem to have something of a real-world problem, there is an apparent disconnect with the physiology that I’ve (so-far) looked at and the results of research (or the real world), many of which are showing greater fat loss with the interval versus steady state exercise mode. In the next two blog posts (this one and Friday’s), I want to look at some of those issues in some detail.

The Now Infamous Tremblay Study

So far as I can tell, one of the first studies to compare fat loss for interval versus steady state training was done by Tremblay back in the mid-90′s. I’m actually fairly sure I was the first one to report this study, in my first book The Ketogenic Diet.

In that study, subjects either followed a fairly standard steady state cardio training program or worked into intervals (after a roughly 4 week base period) over the length of the study. The interval group lost more fat and had a larger drop in skinfolds despite burning significantly fewer calories than the steady state group and training for much less total time.

I’d note that this is where the claim of “Nine times greater fat loss” is coming from. The researchers took the difference in fat loss (three times as much drop in skinfolds) and divided by the total time investment (roughly 1/3rd as long) to get 9 times as much.

I’d also comment that my friend Tom Venuto has recently examined the Tremblay study in some detail in his blog. Parsing the numbers differently, he concluded that the steady state exercise was actually five times as effective.

Pay close attention to the changes in weight in the chart in Tom’s blog: the interval group lost a whopping 0.5 kg (1.1 lbs) over 20 weeks, the steady state group 0.1 kg (0.2 lb). Not as impressive when you look at it that way, unless you consider a 1 pound loss over 20 weeks good.

Other more recent studies, comparing various interval sessions to steady state have often found at least qualitatively similar results, at least in the context of the study (which is almost always untrained individuals who are not doing weight training and not controlling diet), intervals typically generate more fat loss.

As I discussed in in the Research Revivew on The Effects of Exercise Intensity and Duration on the Excess Post-Exercise Oxygen Consumption, the post-exercise calorie burn clearly can’t explain this.

What’s going on?

Muscle Gain

Given that the subjects are typically beginners, it’s possible (although generally unstudied) that the intervals stimulated some muscle gains. The often low total weight loss (despite measurable fat loss) would tend to support that idea, the calories being used for muscle synthesis might add to the effective deficit.

However, what happens if you’ve got someone who is lifting weights as well? What if you have someone who is advanced, they sure as shit won’t be gaining muscle from bike intervals. So even if this is true, it will only hold for rank beginners doing nothing but interval work in the first place.

I’d note that pretty much every study of interval training points out that the intensities used are not sustainable by beginning exercisers in the first place. This has long been one of those ironies surrounding exercise; typically the only people able to burn lots of calories with exercise are trained athletes. And they usually don’t need to lose fat.

Increased Fat Oxidation

A follow-up study by Tremblay actually showed that the interval group saw a significant increase in the enzymes responsible for fat oxidation; surprisingly this effect happened fairly quickly. Given that obese individuals often have a defect in fat oxidation, this could be profoundly beneficial.

This effect is assuredly mediated through both effects on gene expression as well as the glycogen depletion that occurs with high intensity activities; as I’ve mentioned in all of my books glycogen depletion itself enhances full body fat oxidation. If you increase the body’s utilization of fat for the other 23 hours of the day you aren’t exercising, that’s a good thing from a fat loss perspective. Coupled with a calorie reduced and controlled diet, enhancing fatty acid oxidation during the day goes a long way towards explaining enhanced fat loss.

I’d note that steady state cardio is known to cause an increase in fat oxidizing enzymes as well although it typically takes longer than two weeks. I’d also make the same point as above, while the above certainly holds true for intervals versus steady state being done in isolation, what happens if weight training is added.

Of if diet control is placed on the body.  If I deplete someone’s glycogen stores with a combination of full body weight training and carbohydrate restriction (as in the Ultimate Diet 2.0), I can get impressive full body increases in fat oxidation too. In about 3 days.

Read Steady State vs. Intervals: Explaining the Disconnect Part 2