Total Body HIIT Workout HIIT stands for high-intensity interval training. As the name suggests, HIIT workouts involve intervals of high-intensity exercise. Since the exercises are performed at a high level of intensity, the intervals have to be quite short, usually ranging from 30 to 60 seconds. Between each high-intensity interval, you have a short period in which to recover before starting the next. UK Fitness ProJun 22 · 7 min read