What is Hiit training?
Hit or high-intensity interval training involves alternating intervals of both high-intensity activity with low intensity activity or rest these occur over and over and over again. The point to remember here is that when you're in the high intensity interval you are giving it everything you've got and going all out. These workouts typically lasts only a few minutes because they are so exhausting, but they're effective. That's why they're so popular at burning fat. The key difference between hit or high-intensity interval training and moderate intensity continuous exercise is that on the hit side there is a maintenance of a higher range of heart rate as opposed to the moderate intensity phase which can include things like walking on an elliptical or a treadmill.
When you have the higher heart rate range that means more calories are being burned. The beauty of hit is that you can do pretty much any type of exercise. Here again as long as you can go all-out during the high intensity phase. An example would be sprinting like on a track or on an elliptical or treadmill or cycling.
This by no means is an all-inclusive list. Studies have shown that there is a superiority of hit over moderate intensity continuous exercise. In terms of improving insulin sensitivity and aerobic capacity, this type of exercise allows you to workout in a much shorter period of time and burns more calories but also when you're done the workout you continue to burn calories beyond the end of that workout well into the next day.