High-Intensity Interval Training, or HIIT, is a form of cardiovascular interval training that uses short bursts of near-maximal intensity exercise alternating with short periods of rest or active recovery.
These types of exercise sessions usually last about 20 minutes or less because of their high intensity. This timeframe is one of the factors that make HIIT so appealing. The workouts, although challenging, do not take long to complete.
Although this type of exercise stems from sports science, it may also have a place in cardiology. It is well known that heart patients who exercise lower the risk of death or heart disease. Previously though, it was not understood if HIIT would be appropriate for heart patients.
As this type of training started gaining popularity in the general population, researchers applied it to heart patients. They found that patients not only can tolerate this exercise modality but seem to enjoy it.
In the above video, Dr. Gordon Blackburn of the Cleveland Clinic discusses HIIT as an alternative for heart patients.
Sources: The Cleveland Clinic