Researchers find how skeletal muscle adjusts to high-intensity interval training, including alterations to mechanisms crucial for controlling metabolism and muscular contraction.
Research recently published in eLife has provided fresh insight into the effects of high-intensity interval training (HIIT) on human skeletal muscle.
According to the study, HIIT increases the number of skeletal muscle proteins crucial for energy metabolism and muscular contraction and chemically alters important metabolic proteins. These findings may help to explain how HIIT boosts metabolism and open the door to further research on the influence of exercise on these processes.
“Exercising has many beneficial effects that can help prevent and treat metabolic diseases, and this is likely the result of changes in energy use by skeletal muscles. We wanted to understand how exercise alters the muscles’ protein content and how it regulates the activity of these proteins through a chemical reaction called acetylation,” says first and co-corresponding author Morten Hostrup, Associate Professor at the Department of Nutrition, Exercise, and Sports at the University of Copenhagen, Denmark. Acetylation occurs when a member of the small molecule group, acetyl, combines with other molecules and can affect the behavior of proteins.
The scientists enlisted eight healthy, untrained male volunteers for their study, who underwent five weeks of intense cycling training. The guys exercised three times each week, cycling for four minutes at a target heart rate of more than 90% of their maximum, followed by a two-minute break. Each session, they went through this process four to five times.
The scientists examined changes in the makeup of 3,168 proteins in tissue samples taken from the participants’ thighs both before and after the study using a method called mass spectrometry. Additionally, they looked at changes involving 1,263 lysine acetyl-sites on 464 acetylated proteins.
Their analyses showed an increase in the production of proteins used to build mitochondria, which produce energy in cells, and in proteins related to muscle contractions. The team also identified increased acetylation of mitochondrial proteins and enzymes that are involved in the production of cellular energy. Additionally, they observed changes in the number of proteins that reduce the skeletal muscle’s calcium sensitivity, which is essential for muscle contractions.
The results confirm some well-known changes to skeletal muscle proteins that occur after exercise, as well as identify new ones. For example, the reduced calcium sensitivity may explain why it can be harder for muscle contraction to occur after an athlete becomes fatigued. The work also suggests that exercise-induced changes in the regulation of proteins through acetylation may contribute to boosting metabolism.
“Using state-of-the-art proteomics technology, our study provides new information about how skeletal muscle adapts to exercise training, including the identification of novel exercise-regulated proteins and acetyl-sites,” concludes co-corresponding author Atul Deshmukh, Associate Professor at the Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen. “We hope our work will stimulate further research into how exercise helps improve metabolic health in humans.”
Reference: “High-intensity interval training remodels the proteome and acetylome of human skeletal muscle” by Morten Hostrup, Anders Krogh Lemminger, Ben Stocks, Alba Gonzalez-Franquesa, Jeppe Kjærgaard Larsen, Julia Prats Quesada, Martin Thomassen, Brian Tate Weinert, Jens Bangsbo and Atul Shahaji Deshmukh, 31 May 2022, eLife.