HIIT improves metabolic health, new study finds

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New research evaluated the impact of high-intensity interval training (HIIT) on human skeletal muscle and how it impacts metabolism.

The study, published in eLife, and conducted by researchers at the University of Copenhagen in Denmark, explored how exercise alters protein content in the muscles. To do this, the research team engaged eight healthy, untrained male volunteers to complete five weeks of high-intensity cycling training. The men worked out three times per week, finishing four minutes of cycling at a target rate of more than 90 percent of their maximum heart rate followed by a two-minute rest. They repeated this four to five times per workout.

Using a technique called mass spectrometry, researchers analyzed changes to the composition of 3,168 proteins in tissue samples collected from the participants’ thighs before the study and after they completed the training. They also examined changes relating to 1,263 lysine acetyl-sites on 464 acetylated proteins. They found 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 amount of proteins that reduce the skeletal muscle’s calcium sensitivity, which is essential for muscle contractions.

In conclusion, the findings suggest that HIIT boosts the amount of proteins in skeletal muscle that are essential for energy metabolism and muscle contraction, and chemically alters key metabolic proteins. These results may explain the beneficial effects of HIIT on metabolism and pave the way for additional studies exploring how exercise impacts these processes.

“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,” said co-corresponding author Atul Deshmukh, PhD, 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.”