Which benefit is associated with high intensity interval training?

High-intensity interval training (HIIT) is associated with a variety of physiological adaptations, and one significant benefit is improved mitochondrial biogenesis. Mitochondria are the energy-producing structures within cells, and their biogenesis refers to the process by which new mitochondria are formed. HIIT stimulates an increase in mitochondrial density, enabling more efficient energy production, which is particularly beneficial for endurance performance and overall metabolic health.

The mechanisms through which HIIT enhances mitochondrial biogenesis include the activation of specific signaling pathways, such as those involving AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). This leads to improved oxidative capacity of muscle cells and increased endurance, which can confer numerous health benefits, including enhanced fat oxidation and improved glucose metabolism.

In contrast, reduced muscle mass, increased fatigue, and decreased protein turnover are not expected benefits of HIIT. Rather, HIIT can promote muscle preservation or growth, help manage fatigue through improved conditioning, and support increased protein turnover related to muscle recovery and adaptation. Therefore, improved mitochondrial biogenesis is a key advantage of incorporating high-intensity interval training into an exercise regimen.