HIIT versus Cardio for Fat Loss
If you are like the majority of people starting out on a weight loss program, you will most likely start with cardio based exercise. Which for most, is a good start. It is low intensity, easy on the joints and allows you to progressively build a foundation of fitness to then move onto more effective types of training that will give you more results in less time.
However, which is more effective? Let’s take you through a few facts to help you achieve your fat loss goals.
- Cardio is only effective for fat loss in previously sedentary people
- Long duration cardio becomes less effective the more we do it
- Consistent bouts of cardio over 20 minutes make your body more effective at storing fat
- High intensity cardio is generally much more effective for fat loss and improving fitness
General opinion these days is that if you want to lose weight, go for a long jog, cycle, or hop on the x-trainer for an hour. However, it been proven for quite some time that this an ineffective way to lose weight. This is because your body is very good at adapting to your lifestyle, in particular your diet and exercise. Therefore, the more cardio you do, the better your body becomes at using fat as fuel, and so it uses less and less each time. Now we have all heard of the “fat burning zone”, which states that you will burn predominantly fat if you exercise at a certain intensity (about 60%-70% total effort). While this has some scientific basis, the more cardio you do, the less total fat is being burned because the body is becoming more efficient at using it.
Think of it like winning a lottery every time you do cardio, now wouldn’t that be motivating! The first time you might win 75% of $1 million, then, after a month you might only win 75% of $100. Now because fat is your primary energy source, your body starts to think it is very valuable and will therefore, store it more and more. Take for example a female Ironman athlete who trained on average 2 hours a day for 7 months, burnt a quarter of a million calories, and kept to a strict diet. Guess how much weight she lost. Only around 2kg’s! Now if only our body was that good at storing something useful!
So what can we do to ensure we keep burning high amounts of fat? The answer is simple High-Intensity Exercise or HIE. High intensity can be classified as exercise that makes us breathe heavily, and after it’s finished, because we are using oxygen at a faster rate than it can be taken in. Even just 30 seconds of HIE has been shown to be effective at building muscles and burning fat. Time frames of HIE can range from under a minute to an hour, but the longer you do it over 20-30 minutes, the longer you will need to rest, and the less time efficient it will become. 20-30 minutes is a good duration, and can burn as much or even more fat than an hour of jogging.
One of the ways it does this is because it stimulates more type 2 (fast twitch) muscle fibres, which results in the release of certain hormones, and stimulating muscle development and fat loss. This mode of exercise also jacks up your metabolism for a long time afterwards, which means you’re still burning fat after you have finished your HIE session.
So now we know that HIE is better for burning fat, but how does it compare to long duration cardio in terms of fitness? You guessed it, HIE is better for that too. This is also due to your body adapting to exercise. As well as learning to use fat more effectively, it can also learn to use oxygen more effectively, which is in much shorter supply during HIE. HIE is often used by endurance athletes, such as marathon runners, if they have reached a plateau in their exercise capacity. The good thing about HIE is that there are so many ways and time schemes you can do it. From the classic Tabata training (20 seconds on, 10 seconds rest for 8 rounds) using only body weight, to the use of kettlebells, sleds, tires, battle ropes, basically anything that can get you breathing heavily in a short amount of time.
So is there any benefit to low-moderate intensity, extended duration cardio? A few. It still does burn fat when you do it, especially if you don’t exercise regularly. It is also less strenuous, so if you are sore from a hard session the previous day, it can be a good way to enhance recovery and burn some calories at the same time. It also just adds some variety to your workout plan, and many people simply enjoy going for a jog around the park.
In summary, continuous cardio does burn fat, and has its place in a well-balanced exercise regime. However the more fit and experienced you become, the more you should consider opting for a HIE session instead of a 2 hour jog, as you will increase your fitness and lose fat much more effectively.
About the Author:
Phil Peters holds a degree in Exercise Physiology and Sports Science from the University of Queensland, Australia. He specialises in sports performance, fat loss and strategic lifestyle planning for incredible results.