HIIT is considered an ‘alternative’ to so-called steady-state cardio. A training method that promises more results in (much) less time.

WHAT EXACTLY IS HIIT?

HIIT stands for ‘high-intensity interval training’ and is a very intensive form of interval training. In HIIT very intensive efforts are alternated with equally short or often even shorter breaks. This allows you to train very intensively for a longer period of time and to keep your heart rate high.

A well-known example of HIIT is the Tabata method. A Tabata workout consists of eight rounds of 20 seconds of effort followed by 10 seconds of rest. A total workout therefore only takes 8 x 30 seconds, or 4 minutes.

WHY HIIT?

HIIT has its origins in skating and is also widely used in running. But strength athletes can also use HIIT to improve their overall condition and stimulate their fat burning. Yet many bodybuilders do not venture into HIIT. They fear the intense nature of a HIIT workout and fear it will interfere with their progress. That while long-term cardio sessions are associated with higher cortisol levels and muscle breakdown. More on that in a moment.

AFTERBURN

What makes HIIT such an effective method to burn fat? EPOC is often used as an argument for this: excess post-exercise oxygen consumption , in other words the excess oxygen you use after an intensive workout and the extra calories you burn as a result. Also called afterburn effect. However, the magnitude of this effect is grossly exaggerated: in general, but also specifically with regard to HIIT. As you can read in this article, the afterburn effect is only 6-15% of the total calories burned during the activity. And the EPOC of HIIT is not that much greater than that of steady-state cardio: from various studies you can conclude that EPOC after physical activity is mainly related to the total number of calories burned, regardless of the time span (and therefore the intensity).

An example from research: running 20 laps in 1 minute intervals at 105% of VO2max (the maximum amount of oxygen you can absorb each minute), separated by 2 minutes of rest, burned an average of 537 calories during exercise and an additional 64 calories in the 9 hours after the session ^[ iv ] . So not very much.

HORMONAL RESPONSE

But why choose HIIT over steady-state cardio? Just because you save (a lot of) time with HIIT? That could certainly be an argument, but HIIT offers another important advantage over regular, long-term cardio. One benefit that is especially beneficial to bodybuilders: the hormonal response.

Long-term, moderate-intensity cardio, combined with calorie restriction, can cause a sustained rise in the “stress hormone” cortisol. And that may have a catabolic (degrading) effect on muscle tissue. When the cortisol level rises, the body starts to use amino acids from muscle tissue as fuel. Normally, protein utilization as a fuel source is low, but it increases as glucose and glycogen storage decreases. Your liver is able to convert the amino acids from protein to glucose through a process called gluconeogenesis. It does this to maintain glucose levels and carbohydrate stores during periods of prolonged exercise. If you keep your cardio workouts shorter and more intense, those glycogen stores are depleted less than with prolonged cardio training.

HIIT also releases cortisol, but there is also a much greater release of anabolic hormones such as testosterone and growth hormone ^{[ v ][ vi ][ vii ]} . So you get compensation for the negative effects of cortisol. For a bodybuilder who is cutting, that can be important in the battle to maintain muscle. ^[ vii ]

Mind you, HIIT is certainly not a must, even in the cut. Fat loss requires an energy deficit and you initially create that by means of a calorie-restricted diet. Cardio is an optional addition to it. If you need a relatively large amount of cardio because you find strict diets difficult, then HIIT is, as has been shown, a good choice.

SUITABLE EXERCISES

In principle, you can apply the HIIT method to all types of exercises. Or at least all kinds of exercises that you can do quickly, both from strength and endurance training.

HIIT is often applied to endurance sports such as running and cycling. And you can also turn the trusted elliptical cross trainer into a real HIIT machine. Check out how quirky YouTube bodybuilder Chris Jones does his HIIT sessions. If the weather is good, you can also go out on the street and do some sprints. Let the neighbors peek.

You can also use exercises from strength sports – preferably exercises that target as many (large) muscle groups as possible. For this reason, biceps curls and triceps pushdowns, for example, are not suitable exercises for HIIT. The airbike, tire flips, (hill) sprints and thrusters are excellent ways to put HIIT into practice. Bodyweight exercises also work well. For example, you can do one round of push-ups followed by a round of pull-ups.

Though as a bodybuilder, you should be cautious though about using strength exercises in HIIT, because HIIT should not interfere too much with the recovery of your strength training.

Some suggestions for complete HIIT workouts:

HOW OFTEN AND WHEN?

You should not exaggerate HIIT, especially as a bodybuilder. Two to three sessions a week, in combination with your strength training, is about the max. Due to the intensive nature, you cannot do a HIIT training before and better not after your strength training. If you do HIIT before your regular training, you cannot train optimally. If you do HIIT after your regular training, then you cannot do your HIIT workout intensively enough.

You should therefore preferably plan your HIIT training at a different time of the day or on a separate day. We don’t know your training split, but if you train four days a week, for example, you still have three days left to spread your two to three HIIT workouts. And if you train six days a week, you will have to do your strength training in the morning and your HIIT session at a later time.

WHICH METHOD?

The Tabata method is perhaps the best known, but certainly not the only HIIT method. For the beginner, this method may be too intensive, because of the very short rest periods of 10 seconds. As a beginner, you may want to choose a 1:1 (e.g. 30 seconds of effort, 30 seconds of rest) or 1:2 ratio (e.g. 30 seconds of effort, 60 seconds of rest), then slowly increase the intensity through your breaks to shorten. The duration of an effort in a HIIT workout is a maximum of 60 seconds. Personally, we wouldn’t let a break last any longer.

HIIT: THE PITFALLS

The most common mistake with HIIT is that you don’t train intensively enough. Don’t fall into this trap and keep your workout really intensive! How intensive? In principle, you have to be constantly at your anaerobic threshold. If you don’t acidify during a HIIT workout, you are not training intensively enough.

If you want to be sure of the right intensity, measure your heart rate. The guideline for HIIT is 85 percent of your maximum heart rate (that’s 208 – (your age x 0.7)).

And remember, HIIT is not necessary to lose fat. Fat loss starts with a calorie-restricted diet, supplemented with cardio if desired. Non-intensive forms of cardio, especially walking, are also very effective but take more time.

REFERENCES

^[ i ] https://breakingmuscle.com/fitness/the-myth-of-interval-training-and-epoc
^[ ii ] https://www.t-nation.com/training/tip-hiit-it-or-quit-it
^[ iii ] http://jap.physiology.org/content/82/2/661
^[ iv ] http://shapeamerica.tandfonline.com/doi/abs/10.1080/02640410600552064
^[ v ] https://www.omicsonline.org/hormonal-and-metabolic-responses-to-high-intensity-interval-training-2161-0673.1000e132.php?aid=11001
^[ vi ] https://www.researchgate.net/profile/Brendon_Gurd/publication/258334395_Changes_in_mechanisms_proposed_to_mediate_fat_loss_following_an_acute_bout_of_high-intensity_interval_and_endurance_exercise/links/03900000e153c7e
^[ vii ] https://www.ncbi.nlm.nih.gov/pubmed/21785293
^[ viii ] https://www.ncbi.nlm.nih.gov/pubmed/28588097

HIIT it! Practical tips for bodybuilders