As a bodybuilder in the cut, you may be doing some cardio in addition to your strength training. Which type of cardio is better for your physical system: high-intensity interval training (HIIT) or low-intensity steady-state (LISS)? A scientific meta-study provides the answer.
1. You don’t have to do a lot of cardio to lose fat. You can largely suffice with a calorie-restricted diet.
2. If you want to do some cardio anyway, fine. Choose the form of cardio that you find most comfortable.
3. Traditionally, LISS has been the best form of cardio for bodybuilders as it requires the least amount of recovery.
4. HIIT is especially useful if you have little time and/or if you want to boost your overall health and fitness.
LISS VS HIIT
First let’s talk about the differences between these forms of cardio.
LISS is the popular catch-all term for relatively low-intensity exercise styles, that is, with a heart rate around 50 to 65 percent of maximum heart rate. LISS is most commonly associated with running , cycling, brisk walking, swimming, and other physical activities that require longer, low-intensity sessions.
The opposite of LISS is high-intensity interval training, HIIT, which alternates short bursts of high-intensity exercise with low-intensity recovery periods. With HIIT, your heart rate is generally 80 to 95 percent of your maximum heart rate for the high-intensity intervals and 40 to 50 percent for the low-intensity intervals. It is sometimes said that doing HIIT makes you look like a sprinter.
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. You spend much longer with LISS, often 30 to 45 minutes.
Traditionally, bodybuilders have always done LISS. HIIT has only been on the rise in the last ten years. What is better for your physique?
A meta-analysis by Steele et al., based on various studies, concludes that there is no difference between HITT or LISS with regard to body composition. They are both equally efficient, or perhaps inefficient:
Our findings provide compelling evidence that the pattern of intensity of effort and volume during endurance exercise [i.e. interval training vs. continuous training] has minimal influence on longitudinal changes in fat mass and fat-free mass, which are likely to be minimal anyway.
Because HIIT and LISS are very similar physiologically, they also result in similar interference with strength training.
The advantage of LISS is that you can keep the intensity low enough not to cause ‘competition’ with your strength training. Due to the high intensity, this is impossible with HIIT, so you shouldn’t do HITT more than say three times a week. Otherwise, HIIT can even come at the expense of strength gains and lean muscle mass. This despite the so-called hormonal response and afterburn (EPOC) in HIIT, which are too small to positively influence the body composition.
Coach Jackson Peos therefore concludes that HIIT is often incorrectly called ‘anabolic’. HIIT is a useful tool to burn a lot of calories in a short time and thus improve your cardiovascular fitness. On the other hand, LISS burns calories less quickly and builds cardio fitness, but has the advantage that it takes much less recovery. And the latter can be decisive in a (heavy) cut. That’s why we prefer LISS for bodybuilders in a heavy cut.
Please note, for both HIIT and LISS the following applies: preferably do it on a different day than your strength training, or in any case after your strength training.
HIIT AND SPRINTERS
And what about the claim that you build a sprinter’s body with HITT? Coach Menno Henselmans about this:
HIIT doesn’t make you look like a sprinter simply because you don’t train like a sprinter.
Indeed, sprinters typically train with very short sprints, often less than 10 seconds, followed by very long rest intervals, often around 5 minutes. Metabolically, that’s completely different from, say, the Tabata method, with 20-second sprints and 10-second rest intervals. In addition, sprinters mainly get their physique from all the strength training they do, not from sprinting.
Henselmans says the vast majority of his clients don’t need to do cardio to reach their desired body fat percentage. Everything stands or falls with a calorie-restricted diet.
If you do want to do some cardio, Henselmans generally recommends LISS’s old-school bodybuilding approach, on a bike, stairclimber, or elliptical trainer, performed separately from the strength-training workouts.
HIIT is a good option if you want to boost your overall health and condition.
According to muscle-growth expert Brad Schoenfeld in an interview with Men’s Health, the best form of exercise is the one you’re most consistent with. It makes sense that you’re less likely to lace up for that jog if you detest running. Schoenfeld’s colleague Layne Norton agrees.