High Intensity Interval Training for Fat Loss, Performance and…Cardiovascular Disease?

Over the past decade or so there has been a significant shift in the science behind optimal fat loss and performance protocols when it comes to types of training to perform. Many people believed (and still do believe) that low intensity, steady-state activity is best for overall cardiovascular endurance as well as efficient fat loss. This is where the shift has changed the most.


High Intensity Interval Training (HIIT from now on) has taken the country by storm. You can see in the group class offerings at your local fitness center as well as the emergence of studio-like fitness franchise like Orange Theory that base their programming around HIIT. And although HIIT has become so popular because of its’ fantastic ability to melt fat off of you and increase overall performance, there is one particular aspect of development that isn’t talked about as much but holds a much higher importance (at least in the long-run) to our overall health.


But before we get to that, let’s talk about what HIIT really is and get a general understanding of how it effects the body.


What is HIIT, exactly?!


The use of HIIT has been around for ages, but really wasn’t brought into popularity under a formal name until the mid-20th century. The basic idea behind in HIIT is intermittent bursts of work, coupled with a recovery period. The bursts of work can be about any duration you would like, from 10 seconds to 10 minutes, while the rest is typically related to the work interval in some way. For instance, maybe you want to do a work to rest ratio of 1:2. You decide you want to do 30 seconds of work. In order to get 2x the rest, you would have to rest 60 seconds. So you would work hard for 30 seconds and rest for 60 seconds.


As you might guess, the options are endless when it comes to what intervals to do and what rest to take. A simple approach to choosing a HIIT protocol might be:


#1) How Cardiovascularly fit are you?


Meaning, how in shape do you believe you really are. This answer is going to help you decide how intense you will make your intervals. The less fit you believe you are, the lower intensity at which you will perform your intervals. For instance, if you’re in poor cardiovascular shape, you might perform your intervals at 60% intensity.


#2) How long do you want your interval to be?


Some people like longer intervals and some like shorter intervals. Maybe you only want to do 30 seconds of work, or maybe you’re more long distance oriented person and want to do 3 minutes of work. This is mostly up to you.


#3) What work to rest ratio do you want to use?


Work to rest ratio tells us how much rest we will get per unit of work. For instance, if we want a work to rest ratio of 1:4 and are doing 20 seconds of work, our rest would be 4x our work, or 80 seconds. There are 2 rules to follow when choosing your work to rest ration: #1. Consider your answer to “How Cardiovascularly fit are you?”. The less fit you are, the bigger your work to rest ratio should be. #2. Generally speaking, the shorter duration the work period, the longer the rest you want to take.


Finally, figure out a way to fit your protocol into 20 minutes or less. There is a point of diminishing returns with everything, and HIIT is no exception. 20-30 minutes of HIIT will suffice to get you to where you want to go.


How Does HIIT Effect Your Body?


Like I mentioned before, HIIT has exploded on the scene lately due to its’ effectiveness as a fat loss protocol as well as a performance enhancing protocol. And there is little doubt at this point that HIIT is one of the most effective ways to get you moving in either of these directions.


When it comes to fat loss, there have been many studies that have shown how HIIT helps increase your insulin sensitivity (your body will not release insulin as quickly), decrease fasting insulin (the level of insulin in your body in a fasted state) and increase fat oxidation (how efficiently your body burns fat). If you want to read the geeky stuff, THIS RESEARCH REVIEW is a good place to start.


Performance is another aspect of development that is effected when it comes to HIIT. There are a number of ways to performance increases because of HIIT, some of which include increased aerobic and anaerobic fitness as well as skeletal muscle adaptation. Again, read THIS REVIEW if you want to get to the nitty-gritty.


Cardiovascular Disease and HIIT


And even though fat loss and performance are important, they are generally only important in the short-run. Most of us will only be truly concerned about optimal sports performance through high school and, when it comes to fat loss, once you’ve lost the weight…well, you’ve lost the weight. So althought HIIT training should be incorporated into everybody’s programs on a regular basis, these shouldn’t be the prime reasons for long-term results.


The underlying factor that is often overlooked when it comes to HIIT is the impact it has on fighting cardiovascular diseases. These are diseases such as heart valve issues, arrhythmias, heart attack and stroke which are the leading cause of death for both men and women in the United States.


The link between HIIT and cardiovascular disease comes in the form of V02-Max. Your V02-Max is the your body’s maximal oxygen consumption. You know that feeling you get towards the end of a long sprint or long set of squats when you’re huffing and puffing and can’t seem to catch you breath? That means you are close to the maximal amount of oxygen that your body can consume.


There is significant evidence in the correlation between cardiovascular disease and V02-Max. Essentially, the lower your V02-Max, the higher the risk for cardiovascular disease. Now, obviously this is a simplified explanation (and, again, if you’d like to read more into this, you can read THIS RESEARCH ARTICLE by the American Heart Association), but the point is, the less cardiovascular shape you’re in, the more likely you are to encounter cardiovascular disease at some level.


HIIT is the most effective and efficient way for you to improve your cardiovascular fitness. And, like we talked about before, you can adjust your protocol based on your level of fitness. Research shows that both HIGH intensity and MODERATE intensity interval training has been effective in improving V02-Max. So be sure to assess where you are on the fitness continuum before you implement your protocol.


So, implementing a HIIT protocol into you training program will certainly get you leaner, lighter and fitter. And all of these things are important for a healthy, vital life. However, don’t overlook the bigger picture. Your heart is a muscle, too. And keeping it in shape should be your #1 priority. Because your heart is the path to your ultimate life.

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Jerry Scarlato
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Jerry Scarlato

Owner, Fitness Coach at Thrive Fitness
Jerry Scarlato is a Personal Trainer and Entrepreneur who lives in Northern Kentucky. He runs 2 businesses related to health and wellness: Thrive Fitness and Thrive Online. Jerry has been involved in the fitness for his entire adult life, including playing sports through college. Along with being an Entrepreneur, Jerry is a content creator,
Jerry Scarlato
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