Stands for High Intensity Interval Training. It’s basically a fancy way of saying “Sprints”. HIIT sessions are extremely intense short periods of anaerobic activity at near 100% exertion, followed by slightly longer aerobic “rest” periods of around 50% intensity. HIIT sessions are generally between 5-30 minutes long. HIIT training is the most effective form of cardio for fat burning and glucose metabolism.
Stands for Low Intensity Steady State training. Generally best for rest days if you’d still like to get a little cardio in, burns less calories relatively to HIIT training and has a greater chance of catabolising muscle. An example of LISS would be a fast paced walk on a treadmill for about 30- 60 minutes, keeping your heart rate relatively low.