This article was medically reviewed by Joey Thurman, CSCS, CPT, FNS, a Chicago-based fitness expert and creator of Fast Results program. HIIT workouts, or high-intensity interval training ...

There are several reasons why this happens. Firstly, during HIIT training, your body’s oxygen demand exceeds the supply, so your body needs to replenish this post-exercise, and this in turn burns ...

Today we're going to do a High-Intensity Interval Training workout, or HIIT, H-I-I-T. What we'll do is 20 seconds of an exercise, pushing as hard as you can, then taking 10 seconds' rest.