High-intensity interval training, also known as HIIT, was first used in the early twentieth century and popularized later that century to help Olympic athletes improve their results. It is the result of combining high-intensity exercise cycles with low-intensity exercise or rest intervals to do a greater amount of work at a higher intensity during a single exercise session. The researchers claim that HIIT can provide beneficial effects for patients with a chronic disease and should be included in the comprehensive medical management plan. It can improve the functional ability of people with cardiovascular, respiratory, and diabetes diseases.
Ross, L. M., Porter, R. R., & Durstine, J. L. (2016, June). High-intensity interval training (HIIT) for patients with chronic diseases. Journal of sport and health science. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6188712/