Interval training is a type of physical training that involves bursts of high intensity work. This high intensity work is alternated with periods of rest or low activity, the eponymous intervals.
The term can refer to any cardiovascular workout (e.g. cycling, running, rowing, etc.) that involves brief bouts at near-maximum exertion interspersed with periods of lower-intensity activity.
Interval training is often practiced by long distance runners (800 meters and above). Sprinters and footballers have also been known to use this type of training.
Interval training is a favorite of coaches because of its effectiveness in cardiovascular build-up and also its ability to make more well-rounded runners. However, it is also applicable to exercisers as it helps improve exercisers' aerobic capacity to exercise longer at varying intensities.
It has been argued that this method of training may be more effective at inducing fat loss than simply training at a moderate intensity level for the same duration.
High-intensity interval training (HIIT) or sprint interval training is an exercise strategy that is intended to improve performance with short training sessions. HIIT is a form of cardiovascular exercise which is beneficial to burning fat in a short and intense workout.
A HIIT session consists of a warm up period of exercise, followed by six to ten repetitions of high intensity exercise, separated by medium intensity exercise, and ending with a period of cool down exercise. The high intensity exercise should be done at near maximum intensity. The medium exercise should be about 50% intensity.