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HIIT vs Constant running
- Thread starter seyz
- Start date
Probably worth checking out this sticky on HIIT. In particular, I would read the comments that follow the initial post.
http://training.fitness.com/interval-training/hitt-explained-18503.html
http://training.fitness.com/interval-training/hitt-explained-18503.html
I am just wondering, what are the positives and negatives on both? Is it better to rotate between the two of them or just stick to a routine that only involves one of them?
Thanks
For weight loss, you are better off doing HIIT if you are in good enough shape to do HIIT - it is not for beginners IMO.
To build up stamina, you are probably better off doing long, steady runs, but there is debate in the endurance training community on whether you get better results with endurance if you do long steady distance or intervals. I think incorporating both gives the best of both worlds.
ss-cardio versus intervals article
--------------------------------------------------------------------------------
by lyle macdonald
Stead state versus intervals
Over the past month of blogging, I’ve been talking about the current fascination with interval training (for either fat loss or performance) with the main focus being on what I see as a myopic ‘intervals are always superior’ mentality (usually based on poor arguments).
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, this article 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 (with links to each individual post) and then simply point everyone to an article I just added to the main site which basically puts all of the information together.
After a brief introduction to the topic, the first thing I looked at was a recent paper in diabetics 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.
The next piece I wrote 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. Elite marathoners are almost 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 an excessively long (even for me) research review, 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. To put this in perspective, 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 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 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.
Next up, 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 the next post, I examined another recent paper 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 taht 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).
Finally wrapping things up, I started getting to the point this past Monday where 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.
I continued with that theme on Wednesday in where I continued getting to the point and 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 in a newsletter article a while back that I put up on the main page today. 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?
Lyle
Bodyrecomposition - Lyle McDonald
--------------------------------------------------------------------------------
by lyle macdonald
Stead state versus intervals
Over the past month of blogging, I’ve been talking about the current fascination with interval training (for either fat loss or performance) with the main focus being on what I see as a myopic ‘intervals are always superior’ mentality (usually based on poor arguments).
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, this article 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 (with links to each individual post) and then simply point everyone to an article I just added to the main site which basically puts all of the information together.
After a brief introduction to the topic, the first thing I looked at was a recent paper in diabetics 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.
The next piece I wrote 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. Elite marathoners are almost 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 an excessively long (even for me) research review, 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. To put this in perspective, 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 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 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.
Next up, 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 the next post, I examined another recent paper 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 taht 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).
Finally wrapping things up, I started getting to the point this past Monday where 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.
I continued with that theme on Wednesday in where I continued getting to the point and 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 in a newsletter article a while back that I put up on the main page today. 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?
Lyle
Bodyrecomposition - Lyle McDonald
Seyz, it depends on your goals?
Unfortunately Lyle has gone adrift slightly in that post.
It is unequivocal that interval training has been shown to elicit greater fat loss than continuous training. It's as simple as that. I'm not sure why some points were even mentioned, like diabetes improvements. That is for a specific pathological condition, not for the large population who are overweight.
Unfortunately Lyle has gone adrift slightly in that post.
It is unequivocal that interval training has been shown to elicit greater fat loss than continuous training. It's as simple as that. I'm not sure why some points were even mentioned, like diabetes improvements. That is for a specific pathological condition, not for the large population who are overweight.
.
It is unequivocal that interval training has been shown to elicit greater fat loss than continuous training.
wouldnt that depend on the amount of time given to each ie 20mins of HIIT wont burn as much fat as 1hr of ss-cardio.
also wouldnt that depend on the intensity of the continous training and the HIIT as well ie depending how low the slow parts of HIIT are you could actualy be training more intensly doing continous training.
also as lyle states HIIT isn't meant to be done every day so IMO mix it up.
“Steady State Cardio 5 X More Effective Than HIIT????”
Tom Venuto
High Intensity Interval Training, or HIIT for short, has been promoted as one of the most effective training methods ever to come down the pike, both for fat loss and for cardiovascular fitness. One of the most popular claims for HIIT is that it burns “9 times more fat” than conventional (steady state) cardio. This figure was extracted from a study performed by Angelo Tremblay at Laval University in 1994. But what if I told you that HIIT has never been proven to be 9 times more effective than regular cardio… What if I told you that the same study actually shows that HIIT is 5 times less effective than steady state cardio??? Read on and see the proof for yourself.
“There are lies, damned lies, and then there are statistics.”
- Mark Twain
In 1994, a study was published in the scientific journal Metabolism by Angelo Tremblay and his team from the Physical activity sciences laboratory at Laval University in Quebec, Canada. Based on the results of this study, you hear personal trainers across the globe claiming that “HIIT burns 9 times more fat than steady state cardio.”
This claim has often been interpreted by the not so scientifically literate public as meaning something like this: If you burned 3 pounds of fat in 15 weeks on steady state cardio, you would now burn 27 pounds of fat in 15 weeks (3 lbs X 9 times better = 27 lbs).
Although it’s usually not stated as such, frankly, I think this is what some trainers want you to believe, because the programs that some trainers promote are based on convincing you of the vast superiority of HIIT and the “uselessness” of low intensity exercise.
Indeed, higher intensity exercise is more effective and time efficient than lower intensity exercise. The question is, how much more effective? There’s no evidence that the “9 times more fat loss” claim is true outside the specific context in which it was mentioned in this study.
In order to get to the bottom of this, you have to read the full text of the research paper and you have to look very closely at the results.
13 men and 14 women age 18 to 32 started the study. They were broken into two groups, a high intensity intermittent training program (HIIT) and a steady state training program which they referred to as endurance training (ET).
The ET group completed a 20 week steady state aerobic training program on a cycle ergometer 4 times a week for 30 minutes, later progressing to 5 times per week for 45 minutes. The initial intensity was 60% of maximal heart rate reserve, later increasing to 85%.
The HIIT group performed 25-30 minutes of continuous exercise at 70% of maximal heart rate reserve and they also progressively added 35 long and short interval training sessions over a period of 15 weeks. Short work intervals started at 10 then 15 bouts of 15 seconds, increasing to 30 seconds. Long intervals started at 5 bouts of 60 seconds, increasing to 90 seconds. Intensity and duration were progressively increased over the 15 week period.
The results: 3 times greater fat loss in the HIIT group
Even though the energy cost of the exercise performed in the ET group was twice as high as the HIIT group, the sum of the skinfolds (which reflects subcutaneous body fat) in the HIIT group was three times lower than the ET group.
So where did the “9 times greater fat loss” claim come from?
Well, there was a difference in energy cost between groups, so in order to show a comparison of fat loss relative to energy cost, Tremblay wrote,
“It appeared reasonable to correct changes in subcutaneous fat for the total cost of training. This was performed by expressing changes in subcutaneous skinfolds per megajoule of energy expended in each program.”
Translation: The subjects did not lose 9 times more body fat, in absolute terms. But hey, 3 times more fat loss? You’ll gladly take that, right?
Well hold on, because there’s more.
Did you know that in this oft-quoted study, neither group lost much weight? In fact, if you look at the charts, you can see that the HIIT group lost 0.1 kg (63.9 kg before, 63.8 kg after). Yes, the HIIT group lost a whopping 100 grams of weight in 15 weeks!
The ET group lost 0.5 kilograms (60.6 kg before, 60.1 kg after).
Naturally, lack of weight loss while skinfolds decrease could simply mean that body composition improved (lean mass increased), but I think it’s important to highlight the fact that the research study from which the “9 times more fat” claim was derived did not result in ANY significant weight loss after 15 weeks.
Based on these results, if I wanted to manipulate statistics to promote steady state cardio, I could go around telling people, “Research study says steady state cardio (endurance training) results in 5 times more weight loss than high intensity interval training!” Or the reverse, “Clinical trial proves that high intensity interval training is 5 times less effective than steady state cardio!”
Mind you, THIS IS THE SAME STUDY THAT IS MOST OFTEN QUOTED TO SUPPORT HIIT!
If I said 5 X greater weight loss with steady state, I would be telling the truth, wouldn’t I? (100 grams of weight loss vs 500 grams?) Of course, that would be misleading because the weight loss was hardly significant in either group, because it doesn’t distinguish between weight loss and body composition and because interval training IS highly effective. I’m simply being a little facetious in order to make a point: Be careful with statistics. I have seen statistical manipulation used many times in other contexts to deceive unsuspecting consumers.
For example, advertisements for a popular fat burner claim that use of their supplement resulted in twice as much fat loss, based on scientific research. The claim was true. Of course, in the ad, they forget to tell you that after six months, the control group lost no weight, while the supplement group lost only 1.0 kilo. Whoop de doo! ONE KILO of weight loss after going through a six month supply of this “miracle fat burner!”
But I digress…
Back to the HIIT story – there’s even more to it.
In the ET group, there were some funky skinfold and circumference measurements. ALL of the skinfold measurements in the ET group either stayed the same or went down except the calf measurement, which went up.
The girths and skinfold measurements in the limbs went down in the HIIT group, but there wasn’t much difference between HIIT and ET in the trunk skinfolds. These facts are all very easy to miss. I didn’t even notice it myself until exercise physiologist Christian Finn pointed it out to me. Christian said,
“When you look at the changes in the three skinfold measurements taken from the trunk, there wasn’t that much difference between the steady state group (-6.3mm) and the HIIT group (-8.7 mm). So, much of the difference in subcutaneous fat loss between the groups wasn’t because the HIIT group lost more fat, but because the steady state group actually gained fat around the calf muscles. We shouldn’t discount simple measurement error as an explanation for these rather odd results.”
Christian also pointed out that the two test groups were not evenly matched for body composition at the beginning of the study. At the beginning of the study, the starting body fat based on skinfolds in the HIIT group was nearly 20% higher than the ET group. He concluded:
“So while this study is interesting, weaknesses in the methods used to track changes in body composition mean that we should treat the results and conclusions with some caution.”
One beneficial aspect of HIIT that most trainers forget to mention is that HIIT may actually suppress your appetite, while steady state cardio might increase appetite. In a study such as this, however, that can skew the results. If energy intake were not controlled, then some of the greater fat loss in the HIIT group could be due to lowered caloric intake.
Last but not least, I’d like to highlight the words of the researchers themselves in the conclusion of the paper, which confirms the effectiveness of HIIT, but also helps put it in perspective a bit:
“For a given level of energy expenditure, a high intensity training program induces a greater loss of subcutaneous fat compared with a training program of moderate intensity.”
“It is obvious that high intensity exercise cannot be prescribed for individuals at risk for health problems or for obese people who are not used to exercise. In these cases, the most prudent course remains a low intensity exercise program with a progressive increase in duration and frequency of sessions.”
In conclusion, my intention in writing this article wasn’t to be controversial, to be a smart-alec or to criticize HIIT. To the contrary, additional research has continued to support the efficacy of HIIT for fat loss and fitness, not to mention that it is one of the most time efficient ways to do cardiovascular training.
I have recommended HIIT for years in my Burn The Fat, Feed The Muscle program, using a 1:1 long interval approach, which, while only one of many ways to do HIIT, is probably my personal favorite method. However, I also recommend steady state cardio and even low intensity cardio like walking, when it is appropriate.
My intentions for writing this article were four-fold:
1. To encourage you to question where claims come from, especially if they sound too good to be true.
2. To alert you to how advertisers might use research such as this to exaggerate with statistics
3. To encourage the fitness community to swing the pendulum back to center a bit, by not over-selling the benefits of HIIT beyond what can be supported by the scientific research
4. To encourage the fitness community, that even as they praise HIIT, not to condemn lower and moderate intensity forms of cardio.
As the original author of the 1994 HIIT study himself pointed out, HIIT is not for everyone, and cardio should be prescribed with progression. Also, mountains of other research has proven that walking (GASP! - low intensity cardio!) has always been one of the most successful exercise methods for overweight men and women.
There is ample evidence which says that obesity may be the result of a very slight daily energy imbalance, which adds up over time. Therefore, even a small amount of casual exercise or activity, if done consistently, and not compensated for with increased food intake, could reverse the obesity trend. HIIT gets the job done fast, but that doesn’t mean low intensity cardio is useless or that you should abandon your walking program, if you have the time and if that is what you enjoy and if that is what’s working for you in your personal situation.
The mechanisms and reasons why HIIT works so well are numerous and will have to wait for the next newsletter. It goes way beyond more calories burned during the workout.
Until then, train hard and expect success!
Tom Venuto
Tom Venuto
High Intensity Interval Training, or HIIT for short, has been promoted as one of the most effective training methods ever to come down the pike, both for fat loss and for cardiovascular fitness. One of the most popular claims for HIIT is that it burns “9 times more fat” than conventional (steady state) cardio. This figure was extracted from a study performed by Angelo Tremblay at Laval University in 1994. But what if I told you that HIIT has never been proven to be 9 times more effective than regular cardio… What if I told you that the same study actually shows that HIIT is 5 times less effective than steady state cardio??? Read on and see the proof for yourself.
“There are lies, damned lies, and then there are statistics.”
- Mark Twain
In 1994, a study was published in the scientific journal Metabolism by Angelo Tremblay and his team from the Physical activity sciences laboratory at Laval University in Quebec, Canada. Based on the results of this study, you hear personal trainers across the globe claiming that “HIIT burns 9 times more fat than steady state cardio.”
This claim has often been interpreted by the not so scientifically literate public as meaning something like this: If you burned 3 pounds of fat in 15 weeks on steady state cardio, you would now burn 27 pounds of fat in 15 weeks (3 lbs X 9 times better = 27 lbs).
Although it’s usually not stated as such, frankly, I think this is what some trainers want you to believe, because the programs that some trainers promote are based on convincing you of the vast superiority of HIIT and the “uselessness” of low intensity exercise.
Indeed, higher intensity exercise is more effective and time efficient than lower intensity exercise. The question is, how much more effective? There’s no evidence that the “9 times more fat loss” claim is true outside the specific context in which it was mentioned in this study.
In order to get to the bottom of this, you have to read the full text of the research paper and you have to look very closely at the results.
13 men and 14 women age 18 to 32 started the study. They were broken into two groups, a high intensity intermittent training program (HIIT) and a steady state training program which they referred to as endurance training (ET).
The ET group completed a 20 week steady state aerobic training program on a cycle ergometer 4 times a week for 30 minutes, later progressing to 5 times per week for 45 minutes. The initial intensity was 60% of maximal heart rate reserve, later increasing to 85%.
The HIIT group performed 25-30 minutes of continuous exercise at 70% of maximal heart rate reserve and they also progressively added 35 long and short interval training sessions over a period of 15 weeks. Short work intervals started at 10 then 15 bouts of 15 seconds, increasing to 30 seconds. Long intervals started at 5 bouts of 60 seconds, increasing to 90 seconds. Intensity and duration were progressively increased over the 15 week period.
The results: 3 times greater fat loss in the HIIT group
Even though the energy cost of the exercise performed in the ET group was twice as high as the HIIT group, the sum of the skinfolds (which reflects subcutaneous body fat) in the HIIT group was three times lower than the ET group.
So where did the “9 times greater fat loss” claim come from?
Well, there was a difference in energy cost between groups, so in order to show a comparison of fat loss relative to energy cost, Tremblay wrote,
“It appeared reasonable to correct changes in subcutaneous fat for the total cost of training. This was performed by expressing changes in subcutaneous skinfolds per megajoule of energy expended in each program.”
Translation: The subjects did not lose 9 times more body fat, in absolute terms. But hey, 3 times more fat loss? You’ll gladly take that, right?
Well hold on, because there’s more.
Did you know that in this oft-quoted study, neither group lost much weight? In fact, if you look at the charts, you can see that the HIIT group lost 0.1 kg (63.9 kg before, 63.8 kg after). Yes, the HIIT group lost a whopping 100 grams of weight in 15 weeks!
The ET group lost 0.5 kilograms (60.6 kg before, 60.1 kg after).
Naturally, lack of weight loss while skinfolds decrease could simply mean that body composition improved (lean mass increased), but I think it’s important to highlight the fact that the research study from which the “9 times more fat” claim was derived did not result in ANY significant weight loss after 15 weeks.
Based on these results, if I wanted to manipulate statistics to promote steady state cardio, I could go around telling people, “Research study says steady state cardio (endurance training) results in 5 times more weight loss than high intensity interval training!” Or the reverse, “Clinical trial proves that high intensity interval training is 5 times less effective than steady state cardio!”
Mind you, THIS IS THE SAME STUDY THAT IS MOST OFTEN QUOTED TO SUPPORT HIIT!
If I said 5 X greater weight loss with steady state, I would be telling the truth, wouldn’t I? (100 grams of weight loss vs 500 grams?) Of course, that would be misleading because the weight loss was hardly significant in either group, because it doesn’t distinguish between weight loss and body composition and because interval training IS highly effective. I’m simply being a little facetious in order to make a point: Be careful with statistics. I have seen statistical manipulation used many times in other contexts to deceive unsuspecting consumers.
For example, advertisements for a popular fat burner claim that use of their supplement resulted in twice as much fat loss, based on scientific research. The claim was true. Of course, in the ad, they forget to tell you that after six months, the control group lost no weight, while the supplement group lost only 1.0 kilo. Whoop de doo! ONE KILO of weight loss after going through a six month supply of this “miracle fat burner!”
But I digress…
Back to the HIIT story – there’s even more to it.
In the ET group, there were some funky skinfold and circumference measurements. ALL of the skinfold measurements in the ET group either stayed the same or went down except the calf measurement, which went up.
The girths and skinfold measurements in the limbs went down in the HIIT group, but there wasn’t much difference between HIIT and ET in the trunk skinfolds. These facts are all very easy to miss. I didn’t even notice it myself until exercise physiologist Christian Finn pointed it out to me. Christian said,
“When you look at the changes in the three skinfold measurements taken from the trunk, there wasn’t that much difference between the steady state group (-6.3mm) and the HIIT group (-8.7 mm). So, much of the difference in subcutaneous fat loss between the groups wasn’t because the HIIT group lost more fat, but because the steady state group actually gained fat around the calf muscles. We shouldn’t discount simple measurement error as an explanation for these rather odd results.”
Christian also pointed out that the two test groups were not evenly matched for body composition at the beginning of the study. At the beginning of the study, the starting body fat based on skinfolds in the HIIT group was nearly 20% higher than the ET group. He concluded:
“So while this study is interesting, weaknesses in the methods used to track changes in body composition mean that we should treat the results and conclusions with some caution.”
One beneficial aspect of HIIT that most trainers forget to mention is that HIIT may actually suppress your appetite, while steady state cardio might increase appetite. In a study such as this, however, that can skew the results. If energy intake were not controlled, then some of the greater fat loss in the HIIT group could be due to lowered caloric intake.
Last but not least, I’d like to highlight the words of the researchers themselves in the conclusion of the paper, which confirms the effectiveness of HIIT, but also helps put it in perspective a bit:
“For a given level of energy expenditure, a high intensity training program induces a greater loss of subcutaneous fat compared with a training program of moderate intensity.”
“It is obvious that high intensity exercise cannot be prescribed for individuals at risk for health problems or for obese people who are not used to exercise. In these cases, the most prudent course remains a low intensity exercise program with a progressive increase in duration and frequency of sessions.”
In conclusion, my intention in writing this article wasn’t to be controversial, to be a smart-alec or to criticize HIIT. To the contrary, additional research has continued to support the efficacy of HIIT for fat loss and fitness, not to mention that it is one of the most time efficient ways to do cardiovascular training.
I have recommended HIIT for years in my Burn The Fat, Feed The Muscle program, using a 1:1 long interval approach, which, while only one of many ways to do HIIT, is probably my personal favorite method. However, I also recommend steady state cardio and even low intensity cardio like walking, when it is appropriate.
My intentions for writing this article were four-fold:
1. To encourage you to question where claims come from, especially if they sound too good to be true.
2. To alert you to how advertisers might use research such as this to exaggerate with statistics
3. To encourage the fitness community to swing the pendulum back to center a bit, by not over-selling the benefits of HIIT beyond what can be supported by the scientific research
4. To encourage the fitness community, that even as they praise HIIT, not to condemn lower and moderate intensity forms of cardio.
As the original author of the 1994 HIIT study himself pointed out, HIIT is not for everyone, and cardio should be prescribed with progression. Also, mountains of other research has proven that walking (GASP! - low intensity cardio!) has always been one of the most successful exercise methods for overweight men and women.
There is ample evidence which says that obesity may be the result of a very slight daily energy imbalance, which adds up over time. Therefore, even a small amount of casual exercise or activity, if done consistently, and not compensated for with increased food intake, could reverse the obesity trend. HIIT gets the job done fast, but that doesn’t mean low intensity cardio is useless or that you should abandon your walking program, if you have the time and if that is what you enjoy and if that is what’s working for you in your personal situation.
The mechanisms and reasons why HIIT works so well are numerous and will have to wait for the next newsletter. It goes way beyond more calories burned during the workout.
Until then, train hard and expect success!
Tom Venuto
Jill Barker, National Post
Tuesday, Jun 9, 2009
A new study suggests that the rate at which frequently exercised bodies burn calories while at rest is not significantly higher than the rate for less active people. - Yvonne Berg / National Post file photo
There is a long-held belief that exercise can turn you into a fat-burning machine. The idea is based on the suggestion that fat burning occurs not just during exercise but also long after your workout is over. That post-exercise burn, so goes the theory, is instrumental in losing unwanted weight.
As it turns out, however, like so many headlines touting weight-loss miracles, this one is more myth than fact.
"To our surprise, we have found that exercise has little, if any, effect on 24-hour fat oxidation [burning]," declared Edward Melanson, an exercise physiologist from the University of Colorado and lead author in an article from the April issue of Exercise and Sport Sciences Review.
Melanson used an interesting design to challenge the long-held belief that exercise enhances fat burning. Sixty-five candidates of varying fitness level and girth (well- trained and sedentary, lean and obese) all cycled at varied intensities until they burned 400 calories, after which they were monitored for 24 hours - a period that exceeds most other studies by several hours. All were monitored in closed quarters and were able to eat during the 24-hour period. None posted results that suggested enhanced fat burning during or after their workouts.
The study has caused quite a stir among fitness experts who now have to think twice before suggesting that exercise boosts metabolism in the short or long term.
Before putting your feet up in protest, keep in mind that this study in no way diminishes the value of regular exercise. Working up a sweat is still one of the best things you can do for your health. And regardless of the amount of fat you may or may not burn post-workout, there's no denying that a moving body burns more calories per minute than a sedentary one.
The message about fat burning has always been confusing for average exercisers who want to get rid of a little extra baggage. The oft-touted premise that certain forms of exercise or certain intensity levels during a workout can selectively burn off unwanted fat stores is without scientific merit.
In fact, our fixation on fat burning is misguided. When it comes to achieving your weight-loss goals, any calorie you burn is a good one - whether it be in the form of fat, carbohydrate or protein. As long as you burn more calories than you consume, the weight will come off.
As for the much ballyhooed post-exercise after-burn, well, let's just say the number of calories burned is less than impressive.
According to Pascal Imbreault, associate professor at the University of Ottawa's school of human kinetics, any exercise-related after-burn usually runs its course within 15 to 35 minutes of completing a workout. And while the actual number of calories expended during this time varies according to exercise intensity, duration and the body weight of the exerciser, he describes the resulting calorie burn to be "very minimal."
Imbreault suggests that exercise doesn't do much to crank up your metabolism over the long term, either, despite what the headlines in fitness magazines claim.
"Exercise is not that powerful," he said.
Also included in the list of overstated metabolic benefits is the popular belief that adding more muscle to your frame will increase the number of calories you burn at rest.
The idea that muscle is more metabolically active than fat, and therefore burns more calories, is not a fair representation of what really happens, Imbreault says. He claims that active muscle demands far more calories to maintain than muscle that isn't in use. He also suggests that during periods of rest, muscle and fat probably demand roughly the same amount of calories to sustain themselves.
Does that mean all those hours in the weight room were for naught? Relax. The benefits of added muscle don't diminish because you miscalculated how much they contribute toward your daily caloric expenditure. Maintaining and building muscle mass still reduces the risk of injury, makes the accomplishment of daily tasks easier, improves athletic performance and helps you rock a T-shirt.
As for exercise and its role in weight loss, the message couldn't be easier to understand: Use exercise to increase the number of calories you burn. Make smart food choices and trim down your portions to reduce the number of calories you consume. Do that more days than not, and you'll become a calorie-burning machine that slowly but steadily loses excess body weight.
As for fat burning, don't confuse it with the goal of trying to get rid of those love handles. Chipping away at excess flab doesn't require you to selectively burn fat over carbohydrates or protein. Creating a negative energy balance (burning more calories than you consume) is what eats away at fat stores, so get moving. Every calorie burned is one less stored - on the hips or anywhere else.
Tuesday, Jun 9, 2009
A new study suggests that the rate at which frequently exercised bodies burn calories while at rest is not significantly higher than the rate for less active people. - Yvonne Berg / National Post file photo
There is a long-held belief that exercise can turn you into a fat-burning machine. The idea is based on the suggestion that fat burning occurs not just during exercise but also long after your workout is over. That post-exercise burn, so goes the theory, is instrumental in losing unwanted weight.
As it turns out, however, like so many headlines touting weight-loss miracles, this one is more myth than fact.
"To our surprise, we have found that exercise has little, if any, effect on 24-hour fat oxidation [burning]," declared Edward Melanson, an exercise physiologist from the University of Colorado and lead author in an article from the April issue of Exercise and Sport Sciences Review.
Melanson used an interesting design to challenge the long-held belief that exercise enhances fat burning. Sixty-five candidates of varying fitness level and girth (well- trained and sedentary, lean and obese) all cycled at varied intensities until they burned 400 calories, after which they were monitored for 24 hours - a period that exceeds most other studies by several hours. All were monitored in closed quarters and were able to eat during the 24-hour period. None posted results that suggested enhanced fat burning during or after their workouts.
The study has caused quite a stir among fitness experts who now have to think twice before suggesting that exercise boosts metabolism in the short or long term.
Before putting your feet up in protest, keep in mind that this study in no way diminishes the value of regular exercise. Working up a sweat is still one of the best things you can do for your health. And regardless of the amount of fat you may or may not burn post-workout, there's no denying that a moving body burns more calories per minute than a sedentary one.
The message about fat burning has always been confusing for average exercisers who want to get rid of a little extra baggage. The oft-touted premise that certain forms of exercise or certain intensity levels during a workout can selectively burn off unwanted fat stores is without scientific merit.
In fact, our fixation on fat burning is misguided. When it comes to achieving your weight-loss goals, any calorie you burn is a good one - whether it be in the form of fat, carbohydrate or protein. As long as you burn more calories than you consume, the weight will come off.
As for the much ballyhooed post-exercise after-burn, well, let's just say the number of calories burned is less than impressive.
According to Pascal Imbreault, associate professor at the University of Ottawa's school of human kinetics, any exercise-related after-burn usually runs its course within 15 to 35 minutes of completing a workout. And while the actual number of calories expended during this time varies according to exercise intensity, duration and the body weight of the exerciser, he describes the resulting calorie burn to be "very minimal."
Imbreault suggests that exercise doesn't do much to crank up your metabolism over the long term, either, despite what the headlines in fitness magazines claim.
"Exercise is not that powerful," he said.
Also included in the list of overstated metabolic benefits is the popular belief that adding more muscle to your frame will increase the number of calories you burn at rest.
The idea that muscle is more metabolically active than fat, and therefore burns more calories, is not a fair representation of what really happens, Imbreault says. He claims that active muscle demands far more calories to maintain than muscle that isn't in use. He also suggests that during periods of rest, muscle and fat probably demand roughly the same amount of calories to sustain themselves.
Does that mean all those hours in the weight room were for naught? Relax. The benefits of added muscle don't diminish because you miscalculated how much they contribute toward your daily caloric expenditure. Maintaining and building muscle mass still reduces the risk of injury, makes the accomplishment of daily tasks easier, improves athletic performance and helps you rock a T-shirt.
As for exercise and its role in weight loss, the message couldn't be easier to understand: Use exercise to increase the number of calories you burn. Make smart food choices and trim down your portions to reduce the number of calories you consume. Do that more days than not, and you'll become a calorie-burning machine that slowly but steadily loses excess body weight.
As for fat burning, don't confuse it with the goal of trying to get rid of those love handles. Chipping away at excess flab doesn't require you to selectively burn fat over carbohydrates or protein. Creating a negative energy balance (burning more calories than you consume) is what eats away at fat stores, so get moving. Every calorie burned is one less stored - on the hips or anywhere else.
wouldnt that depend on the amount of time given to each ie 20mins of HIIT wont burn as much fat as 1hr of ss-cardio.
also wouldnt that depend on the intensity of the continous training and the HIIT as well ie depending how low the slow parts of HIIT are you could actualy be training more intensly doing continous training.
also as lyle states HIIT isn't meant to be done every day so IMO mix it up.
Yeah I agree, mix it up.
All i'm saying is that HIIT (not any form willy nilly), but specific exercises elicit catecholamine release which is a potent fat burner. Many overweight people will find it hard to lose fat, even if they cycle continuously for an hour - they're just resistant.