Evidence-Based Effects of High-Intensity Interval Training on Exercise Capacity and Health: A Review with Historical Perspective

Abstract

Engaging in regular exercise results in a range of physiological adaptations offering benefits for exercise capacity and health, independent of age, gender or the presence of chronic diseases. Accumulating evidence shows that lack of time is a major impediment to exercise, causing physical inactivity worldwide. This issue has resulted in momentum for interval training models known to elicit higher enjoyment and induce adaptations similar to or greater than moderate-intensity continuous training, despite a lower total exercise volume. Although there is no universal definition, high-intensity interval exercise is characterized by repeated short bursts of intense activity, performed with a “near maximal” or “all-out” effort corresponding to ≥90% of maximal oxygen uptake or >75% of maximal power, with periods of rest or low-intensity exercise. Research has indicated that high-intensity interval training induces numerous physiological adaptations that improve exercise capacity (maximal oxygen uptake, aerobic endurance, anaerobic capacity etc.) and metabolic health in both clinical and healthy (athletes, active and inactive individuals without any apparent disease or disorder) populations. In this paper, a brief history of high-intensity interval training is presented, based on the novel findings of some selected studies on exercise capacity and health, starting from the early 1920s to date. Further, an overview of the mechanisms underlying the physiological adaptations in response to high-intensity interval training is provided.

Effects of high-intensity interval training (HIIT) and sprint interval training (SIT) on fat oxidation during exercise: a systematic review and meta-analysis

“…In recent years, effects of high-intensity interval training (HIIT) and sprint interval training (SIT) on cardio-metabolic outcomes have been widely investigated 1 2. A large number of adults engage in this type of exercise to improve their health and fitness 3.…”

Physiological Responses to Low-Volume Interval Training in Women

“…Our understanding of physiological adaptations to interval training is primarily a result of research conducted in men or mixed-cohorts of men and women. A relatively limited understanding of interval training responses in women has recently been recognized [ 10 – 13 ], which is perhaps unsurprising given that women are known to be underrepresented as participants in exercise physiology research [ 14 – 16 ]. However, there are well-recognized sex differences in physiological systems at rest and in responses to acute exercise [ 17 ] that may result in sex-specific physiological and health-related adaptations to interval training.…”

The Effect of a Sprint Interval and Resistance Training Program on Body Composition, Aerobic Fitness, and Self-regulation in Young Women

“…It has been proposed that activating and building muscle, while participating in high intensity cardiovascular training improves metabolic system components (MacDougall et al, 1998;MacInnis & Gibala, 2017). These improvements allow total energy expenditure increases, beneficing the reduction of body fat content (Atakan et al, 2021;Skelly et al, 2021).…”