High-Intensity Interval Training or HIIT, due to its acronym, is an effective method to reduce fat tissue in a short time consisting of several short intervals at high intensities and with full (or near) rest between sets.
That is not a new method, in fact, it is a form of training used by athletes already used for more than a century and until recently has been studied more rigorously from the scientific field of sports sciences and physical activity, to determine morphophysiological changes and adaptations in different population types.
How does it work?
The HIIT, allows a great calorie burning, in a short time. A session can take between 20 to 30 or even less time, as intense work is sought at agreed intervals, bringing the body to the limit between these intervals and with short rest spaces.
There are estimates of calorie burning between 200 and up for 20 min or less work. That is is a great number, especially for those who have a very limited time available to exercising. Many studies have demonstrated the superiority of this type of training in the last decades to improve not only cardiovascular endurance but also fat burning.
How is it possible to burn fatter with anaerobic workouts, which mainly use glycogen (carbohydrate) as energy, than with aerobic training, which uses more% fat as an energy substrate? There are two main reasons:
- The different hormonal response, with more production of testosterone and growth hormone (study). Also, this type of training greatly improves insulin sensitivity in sedentary people (study). This means less likely to accumulate fat and more easily to use as fuel (burn it).
- Post-training energy expenditure. When you finish training, it is time for your body to recover, which requires oxygen.
How to use gym equipment at the beginning
- Static bike: Starting with the static bike is a safe way to experiment with high intensity.
- Tape: The main problem of using the tape to perform intervals is the time it takes to accelerate and stop, so you will have to leave the tape running and jump by putting your feet on the sides when you complete each interval. I recommend at the beginning that you use a certain inclination, to simulate running on a slope. This allows you to increase the intensity without increasing the speed too much.
- Elliptical: allows you to train standing, involving the upper body. And it does not force you to choose between 1) running and destroying your knees and 2) pedaling and destroying your manhood.
- Rowing: Better choice than all of the above, and maybe the only machine you’ll see in a CrossFit gym. Fortunately, they are becoming more frequent in conventional gyms. But undoubtedly, all of the above are intermediate steps.
How can I apply it?
There are several options to perform this type of exercise, to conclude there are some very effective.
HIIT Short 30 seconds: 6-8 series (of the specific exercise) with intervals of 20 seconds (maximum intensity) and recoveries of 10 seconds (passive recovery). For trained people. Or progressive intervals between week and week, for untrained people, example:
Two sets of 4 intervals from 1 minute to 70% with recoveries of 3 min. Total 16 min approximately. For not trained and increase the next day more series versus intensity. Before choosing one of these options, you must be sure that you can withstand the intensity of this great exercise, it does not make sense to hurt yourself, on the contrary, the objective should be to improve the physical condition.
If you have a heart rate monitor, you can use your heart to set the recovery time. For example, the high effort for 15 seconds, in which your pulsations will rise to 170-180, and rest until they fall to 120-130. The main advantage of the HIIT is that it adjusts the recovery time to the fitness level of each. Record the time it takes to reduce the pulsations, and you will see how little by little your recovery time is decreasing.
There are many benefits. However, the first and most important ones to consider are:
- It improves insulin sensitivity.
- Improvement in cardiorespiratory capacity.
- Reduce body fat.
The review by Boutcher (2011), according to Borreani & Burial, indicates that intermittent high-intensity exercise is effective and safe to use. Benefits include losing abdominal and subcutaneous fat, improving VO2max and improving insulin sensitivity, even more than others modes of exercise at a steady intensity.
What risks does it have and what care should I take?
Some risks of this training we can find the following ones since it is a system of training of high intensity, where it takes the body to its limit. It should therefore be done under an expert’s supervision. Risks are present, such as:
- The risk of skeletal muscle injury.
- The risk of exercise-induced bronchospasm.
- The risk of the acute cardiovascular event.
These risk can be prevented with the proper guidance of a specialized instructor and medical guidelines. HIIT can be an effective method to burn fat in a short time, but you should be cautious when practicing it.