HIIT versus steady-state aerobic exercise
Examining current studies, Zuhl and Kravitz compared the benefits of endurance exercise with HIIT. They concluded that both HIIT and continuous aerobic programs improve cardiovascular and musculoskeletal adaptations, but in some circumstances, HIIT may provide better improvements and in less time. Among the reported findings from the studies were:
Cardiovascular responses:
Maximal aerobic capacity, heart mass and contractibility, and stroke volume (the amount of blood the heart pumps in one beat) improve at a greater rate with HIIT compared to continuous conditioning. Interval training gains occur more quickly and with fewer sessions.
Musculoskeletal responses:
Increasing the size and number of mitochondria (the power plant of the cells) ensures more energy is available to the working muscles, so people can move at higher intensities for longer periods without feeling fatigued. Higher levels of mitochondrial enzymes lead to a more effective use of fat and carbohydrates for fueling the body. Although they utilize different pathways, both HIIT and continuous aerobic training result in improvements, and yet a couple of studies reveal greater gains with HIIT, within a shorter period of time. HIIT participants have higher oxygen consumption and caloric expenditure post exercise, for example.