For the past decade I have intermittently written about the effects of exercise on health and body composition (primarily weight loss). My own descent and resurrection from Obesity is well detailed on the Ultra Strength Fat Furnace page in graphic fashion. At that time I also obtained my CPT ( personal Trainer) certificate and began what would amount to a biannual sojourn to Boca Raton and the Institute of Human Performance to visit then Guru now Guru and dear friend Juan Carlos Santana.

I have learned an awful lot from Carlos and it has spurred my continued study of Exercise Physiology, something I obtained a Masters Degree in many years ago.

Along with over a decade of medical practice and another decade in supplement design all interspersed with tons of public speaking teaching normal people and doctors, I distilled one of the most common questions I get asked about exercise into the title of this blog.

“Doc what is the best kind of exercise?!”  I must get asked that 100 times a year from all kinds of people in all kinds of places.  I often give them JC’s answer: The best exercise is the one YOU do!

While this may sound like I am running from the issue it is not. JC has captured the central conundrum of exercise- We can’t get people to do enough of it regularly! Now that is a whole ‘nother lecture so I’ll save that and give my next most common answer:

It depends.

It depends very much on what you want. So then I have to go down that garden pathway with the person and find out what level of motivation, starting fitness and health and realistically what they are likely to stick with.

No mean feat.

The answer I most commonly get is, “Doc I want to lose this excess body fat!  But I also want to have a great body be healthy and still feel attractive. I want fat loss strength and flexibility. I want to be sexy and have a high level of endurance. I want a six pack (guys) and a nice butt (girls). I don’t want to be muscle bound but I want to have muscles. I want to get rid of this belly (guys) and the muffin top (girls).  Oh yeah and I don’t want to be tired all the time. I don’t want to spend much money or invest much time either because I am super busy with all the other stuff that I have somehow decided is far more important than my health. I still need to watch my favorite TV shows and eat out 5 times a week at least. By the way will I have to diet to get to where I want? I hope not. Can’t I just exercise 20 minutes 3x a week like it says on www.miraclebodyinfiveminutesaday.com ?” (Not a real link!)

In other words they want everything.

Not once has anyone ever said, “I want to do the exercise that helps me age most gracefully!” And rarely does anyone say “I want to learn to move better.”

There was this guy named Hans Seyle back in the 1930’s who coined the term adaptation as it applies to the body’s response to exercise. If you keep his principle of adaptation in mind you will understand the body becomes a mirror of the stimulus you give it. Power lifters get powerful and strong. They don’t always look that aesthetically pleasing.  Body builders get less strong significantly bigger (steroids aside) and much more aesthetically pleasing as long as they don’t go overboard. Runners tend to get scrawny in weak looking but they can go forever. And so on and so forth. Ultimately and this is just my opinion Gymnasts for men and skaters for women have the best overall aesthetically pleasing looks.

The point is you become a mirror of the kind of stimulus you give your body so chose wisely and don’t expect running to make you big by itself or power lifting to make you ultra lean by itself.

When I wrote my portion of our book “The Immortality Edge” I had had a lot of exposure to people who advocated Sprint or High Intensity Interval Training (HIIT).Two of the biggest pioneers were Matt Furey and Phil Campbell in that order and were among the first to fuel the fires of what would become the modern HIIT craze.

In our book we wrote that HIIT was the most efficient way to get in shape, maintain health and body weight. We also wrote about its effects on telomere length which is actually shared by Long Slow Distance (LSD).

I chose HIIT type training for the following reasons:

1)      It required only 30 min or so to get a great workout

2)      It can be done as almost zero impact in the pool

3)      It seems to be the fastest way to increase your cardiovascular fitness rapidly at least to a point.

4)      There is less of a tendency to stimulate the monstrous appetite that seems to follow really Long LSD exercise

5)      Bottom line this is a very efficient way to get in shape

6)      The contribution of EPOC Excess Post Exercise Oxygen Consumption was supposed to be enough to add hundreds of calories to the overall calorie burn well beyond the time spent exercising. I had read some early studies that noted up to 600 calories more above and beyond whatever was burned during the exercise bout itself.

So EPOC became the buzz word for fat loss, sexy body composition and spiritual transformation and EPOC became the ‘secret’ to all good things that was defended by its faithful legion.But during my observations of how this type training affected my body I found I did not agree with the last point..  As per my usual approach of, “Gee this is pretty important since the whole premise is built on it. If I can I need to be sure that it is true or not true”, I found a simple way to do some research.

I found a device that accurately measures RMR and MR under other circumstances several years ago called Body Gem.  I initially used this device to evaluate 2 things:  The effects of exercise on me and a few willing “guinea pigs”, and the effects of what was then new, Ultra Strength Fat Furnace to the mix.

What I found was I did not lose weight on interval training alone. In addition I did not have the “getting ripped effect” where body composition changed and body fat melted off me*. This was important because advocates of HIIT defended and marketed both of things like crazy.  Moreover I did not find the Effect of EPOC to be all that earth shattering.  Even with Tabata type intervals I only burned around 220 calories above resting and in me at least the level of increased metabolism lasted far less than the 24 to 36 hours that were originally touted. If you think about it in terms of weight loss and body composition you would want more calories burned than you take in and you would somehow like to shunt those calories away from muscle and into fat. Both were purported benefits of HIIT.

When I added the Ultra Strength Fat Furnace I was able to document on myself and several others around about 600 calories total excess burned (including the 200 from exercise) and see the effect lasting almost a full 24 hours although the level of burn fell off progressively from the time of exercise.

What I ultimately concluded was:

1)      In a well trained middle aged man trying to lose weight HIIT alone when adjusted for the progressive loss of effect over several hours probably was good for 100 calories of extra energy burned. My volunteers (all 4 of them!) had similar results.

2)      By adding a thermogenic supplement and adjusting for progressive loss of effect over time (although a 2 or 3X a day dose routine mitigated this somewhat) I could account for about 400 calories more. Again this is above and beyond the calorie burn of the HIIT session which was usually a 30 minute session with 90 to 92% heart rate for 30 second intervals repeated 8 times. That accounted for another 250 calories or so.

3)      HIIT alone was not going to help with weight loss although it was effective for weight maintenance. Adding a thermogenic definitely made weight loss easier and rather dramatic because 600 calories extra everyday for 6 weeks adds up to serious weight loss!

4)      EPOC was at least in me way overestimated even when different lengths and times of intervals were used. I started with traditional Tabata type intervals on a treadmill or stationary bike at first.

5)      To get the kind of fitness level and body I wanted I had to use more or less standard resistance training and some LSD as well. If the LSD could integrate some intervals (brutally hard to do!) it had even more benefit!

6)      Contrary to what the Gurus had written, LSD also had some EPOC, in some cases more than HIIT!

It turns out that several years after my little personal study several bona fide scientific studies were done and they showed the following.

The maximum EPOC from HIIT training was only 10% of the actual total calorie burn, was long gone after less than 6 hours, maxed out at 220 Cal which again was a spot measurement and fell of the further you went out from the actual exercise. It was long gone the same day and lasted nowhere near the purported 24 hours.

Stated another way HIIT calories come mainly from the actual bout of exercise not the EPOC- something I found to be true years earlier in my own case.

Now here is the thing. I still stand our recommendations in the Immortality Edge because HIIT may actually work better for out of shape people to get them in shape than any other type of exercise.  It certainly works faster!  Depending on what type of hit you do you will get some different results. When I was doing my personal study I eventually settled on 4 minute intervals at 85% heart rate max ( and this was controlled by using a HR monitor) with anywhere from 1 to 3 minutes recovery depending on where my fitness level was.  Repeats were 6 to 8 and I did these on a Schwinn Airdyne cycle which remains my favorite low impact device.  I did my Tabata’s (30 seconds on full and 30 to 60 seconds off) with a flotation vest in deep water at the pool.

When you do the longer lower intensity intervals it has been shown to improve your heart rate and “cardio” conditioning more than the really short super high intensity ones which develop explosive strength more.  As you go longer the contribution of aerobic (burning oxygen) metabolism goes up so this makes sense.

All HIIT had very positive benefits on metabolic parameters like insulin; blood lipids etc so from a health perspective it seems you can get the same benefits as LSD in less time.

What did I learn?

HIIT is very efficient and very useful. It is a great way to “get” in shape or get to the next level of fitness.  It has great metabolic effects. It is not, at least for me and my co-crazies, a way of losing weight or changing body composition by itself. It requires support from other forms of exercise including LSD.

So HIIT is slowly coming down off its high horse and LSD is resuming its rightful place among exercise.  This upsets a lot of people.  I can recall a Gynecologist publically ridiculing me and humiliating himself by angrily telling me I was FOS when I said we are always in the fat burning zone except when we are doing HIIT! He insisted incorrectly that you only burn fat when you hit 90% of your Heart Rate and that this was the “Fat Burning Zone”. This is what happens when people get their information from the internet and believe people who “look” credible but are themselves FOS.

HIIT burns more fat after in its EPOC phase but as we see that was way over estimated. During your HIIT session you are actually using the glycolytic (sugar burning lactate producing) pathways. The angry Gynecologist had done something I see all to commonly these days. He let an internet site or Guru make him forget his education in favor of popular public opinion. Destroying a myth is not a great way to win friends and influence people!

And what happened to all the HIIT gurus?  They are still out there quoting the old studies done with old inaccurate methodology and study design.  The courses and books touting “Get Ripped”  “Afterburn” and “Destroying the Fat Loss Dogma” are still referenced as gospel truth. The information is still quoted as factual, and their devoted legions are still angrily lashing out at me.  I wouldn’t be a bit surprised if I get some comments on this blog that way even though I have had very positive things to say about HIIT.

In the meantime I still stand by my original answer to the question, “Doc what is the best form of exercise?”

It depends.

All the Best, Dr Dave

*There are several well known videos and highly respected trainers who have shown wonderful transformations in their athletes by adding HIIT training and decreasing other forms of training during this time. Tabata the Japanese speed skating coach had great results with his speed skaters in competition and noted remarkable increases in their aerobic capacity. Here’s the thing. These people were all Olympic level athletes. They were already at a super human level of fitness and probably needed one tweak to their training to change their outcomes. That tweak was the metabolic boost given by HIIT but it was contingent on a couple of things: They were quite YOUNG like under 30. They were already in tremendous shape and could tolerate maximal or even “supra” maximal stimulus without whining or getting injured. Their training environment and nutrition were strictly controlled and they did not do other things like try to earn a living. And I guarantee you they did a ton of other stuff besides just HIIT, including some LSD and weight training.

When these principles were applied to even the average active young person the results were less stellar. In the middle aged about to get sick group, you know the 50 something fat  metabolic early diabetic men, the calorie burns were flat out disappointing even though they were at 85% max heart rate. They stayed kinda fat middle aged and frumpy!  But, they got healthier in a big way quick. In other words it not only depends on what YOU want but WHERE you are starting from and how far you can actually go!

References: Total daily energy expenditure is increased following a single bout of sprint interval training

Physiol Rep. 2013 October; 1(5): e00131.

Application of the Speed-Duration Relationship to Normalize the Intensity of High-Intensity Interval Training

PLoS One. 2013; 8(11): e76420.

Sports Med. 2003;33(14):1037-60.

Effect of exercise intensity, duration and mode on post-exercise oxygen consumption.

Børsheim E, Bahr R.

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