Steady State vs. Intervals: Explaining the Disconnect Part 2

In Steady State vs. Intervals: Explaining the Disconnect Part 1, I started to examine some other physiological explanations (outside of EPOC) to potentially explain the seeming disconnect between the total irrelevancy of EPOC and both the research and real-world fat loss results from interval training. I’m going to continue and conclude that discussion today by looking at some other mechanisms by which interval training may be affecting fat loss in both research and the real world.


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



4 thoughts on “Steady State vs. Intervals: Explaining the Disconnect Part 2

  1. Lyle, this site is really interesting, and I’ve been soaking up some very useful information over the past few days – thanks.

    One question – if HIIT does suppress appetite, does this not make it a useful tool for the person who is intentionally trying to reduce their calorie intake (i.e. someone on a diet)?
    I appreciate that those who analysed the study may have drawn the wrong conclusions vis-a-vis cause and effect, but if I am trying to reduce total calories consumed and can perform an exercise that will suppress my own appetite then surely this is a good thing,

  2. The impact of exercise on appetite is much more complex than I made it sound in the article above (e.g. some people come out of activity hungrier for either psychological or physiological reasons).

    I was just trying to find potential reasons for the apparent disconnect between theory and reality. At some point in the future, I’ll be looking at the impact of exercise on appetite/fat loss in a full feature article.

  3. I ‘stumbled’ upon your site. First, this is great info, by far some of the best (and most accurate) out there. The internet is great, but unfortunately there is so much “bogus” information out there!

    I have a quick question, really just want to get some feedback. I’m a 54 year old former college wrestler and coach. My body can’t really take the pounding of live wrestling anymore, although I do get on the mat and drill with my sons on occasions (don’t like drilling with people I don’t know, most are clueless and don’t know the difference between drilling and live). Staying in shape is important and my time is somewhat limited. I’m “old school” in my workout philosophy of ‘go hard, keep it short, keep it intense’, get out. For several months now my workouts have consisted of running stairs (various routines that I mix up) and lifting, with some jump rope thrown in to mix it up. My stair routines vary, but typically I use the 3 flights (72 steps) at the back of my building. Some days I just run up and down for around 25 minutes, most days I work in sets of sprints, and I mix those up as well. For example one day I may run up (and down) twice (the full 72 steps) then sprint a set (taking 2 steps at a time). Six sets of these, plus walking one in the beginning and one at the end, is a total of 20 full sets, 12 running, 6 sprinting. To mix it up, on other days I will run 4, sprint 2, 3 sets of these. Same number of total flights – running and sprinting, just different order to shake things up.

    After the stairs I walk to the other side of the building and hit the weights for around 20 minutes. I mix up those routines as well, keeping the focus on the compound movements like squats, rows, deadlifts, benches, standing militaries… I do everything with dumbbells and mix up the set/rep/ and weight (poundage) sometimes doing sets of 12 with moderate weights, other times going as heavy as I can for sets of 5 reps (usually 3 sets with both formats). Then other days it’s just lots of pull-ups, dips, push-ups neck and ab work (those days I usually don’t run the stairs and jump rope for about 15 minutes after.)

    Any thoughts on these routines?

    Thanks, Phil

  4. Excellent post, Lyle. I always laugh whenever I hear someone touting the superiority of HIIT over steady state cardio for fat loss. What’s that saying about how if you repeat a lie often enough, people start to accept it as the truth? The Tremblay study is a perfect example of that. The pro-interval crowd likes to say that HIIT is 9 times more effective than steady state, but I’m willing to best most of these people can’t even cite where they came up with that figure. Of the ones who can, how many even bothered to read the original study to understand what it was really saying? Apparently not many.

Leave a Comment