High intensity interval training vs moderate intensity continuous training in the management of metabolic type disease

Previously, the use of moderate-intensity continuous training (MICT) has generally been considered the most beneficial exercise treatment modality for the prevention/management of metabolic type disease. More recently, however, high-intensity interval training (HIIT) has emerged into the clinical setting as a potential alternative to traditional MICT in the management of such diseases, but the comparative effects are not well understood. Use of HIIT has the potential to induce favorable physiological remodeling that is similar or even superior to MICT, despite a considerably lower exercise volume and time commitment. Many studies have therefore examined the efficacy of HIIT relative to MICT with respect to reducing the development and progression of numerous metabolic conditions including obesity, type 2 diabetes, and the metabolic syndrome. Despite this, however, the efficacy of HIIT relative to MICT in reversing the specific symptoms and adverse effects of those at risk of, or afflicted with metabolic disease is not well understood. Moreover, HIIT is often perceived as very stressful and demanding, which could potentially render it unsafe and/or unappealing for clinical populations whom are already at a higher risk of experiencing adverse events. Furthermore, the optimal prescriptive variables (volume, intensity, duration, rest) of a HIIT protocol that elicit the greatest benefits for each of the aforementioned clinical cohorts have not been established. This review article aims to explore the use of HIIT with respect to the above. Firstly, the efficacy of HIIT is examined relative to MICT in the management of metabolic diseases, with particular relevance to physiological adaptations, health outcomes, and potential mechanisms. Secondly, the potential safety issues relating to the suitability and tolerability of HIIT for clinical populations, as well as the optimal HIIT prescriptive variables for such clinical populations are discussed.