Is interval training the magic bullet for fat loss?

high intensity rope workout

A recent study published in the British Journal of Sports Medicine analyzed 36 English, Spanish and Portuguese language scientific research papers that compared the effects of high intensity interval training , sprint-interval training and moderate-intensity continuous training exercise on fat loss and changes in body composition. The study provided a meta-analysis of previous studies that looked at the effect of exercise on fat loss and found that while all three types of exercise resulted in similar amounts of absolute fat loss and favorable changes in body composition, in general, the high-intensity interval (HIIT)  and sprint-intensity training (SIT) groups lost significantly more fat that the moderate-intensity continuous training (MOD) group. In fact, the HIIT group 

What is Interval Training?

Fundamentally, any kind of interval training has a exercise period portion followed by a resting or recovery portion and is usually repetitive, meaning multiple exercise/recovery exercise sessions are performed. The benefit is that high-intensity exercise provides a high load on the body over a shorter period of time and also improves the anaerobic exercise system. Most low-intensity and moderate-intensity exercises such as walking or jogging work mostly on aerobic energy systems.

What is High-Intensity Interval Training?

High Intensity Interval Training, also called HIIT or HIT is usually defined as a “near-maximum” exercise effort where heart rate reaches above 80% of the athlete’s predicted maximum heart rate.

What is Sprint-Intensity Training?

Sprint-Intensity Training is another type of interval exercise training which has an even a higher intensity level than High-Intensity interval training or HIIT and is considered an “all-out” effort such as 40 or 100 meter sprints.

Is there a difference between HIIT and sprint-intensity training?What is moderate-continuous exercise training?

Moderate-continuous training is the type of “cardio” that most of us are familiar with – running on a treadmill, swimming laps in the pool or cycling. Heart rate and exercise effort are at a more sustainable level and these exercises can be performed for much longer. 

Essentially the study is compared the effect of “all-out” exercises like sprints, to high-intensity exercises like burpees, 45 to 60 second “near-max” exercise efforts and moderate-continuous exercise like walking or jogging on a treadmill.

The study authors were looking to see if a shorter duration or time of exercise done an higher intensity had any postivie or negative impacts on weight or fat loss when compared to the standard recommendations of 30 minutes or more of moderate exercise.



RB Viana, JP Araújo Naves, VS Coswig, et al, “Is interval training the magic bullet for fat loss? A systematic review and meta-analysis comparing moderate-intensity continuous training with high-intensity interval training (HIIT)”, British Journal of Sports Medicine, 2019;

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