New Study Reveals HIIT May Alter Metabolism
Researchers hope that the findings will spur further investigation into how exercise improves metabolic health
A study in men has revealed the effects of high-intensity interval training (HIIT) on the human skeletal muscle. Researchers from the University of Copenhagen conducted the study, which was published in eLife.
According to the findings, HIIT fitness exercises can increase the amount of proteins in the skeletal muscle, which are required for energy metabolism and muscle contraction. Engaging in HIIT may also chemically alter key metabolic proteins, say researchers.
HIIT already has a slew of major health benefits, such as reducing blood sugar and increased calorie burn, but these new findings from the University of Copenhagen reveal metabolism benefits and could prompt further research.
“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, as Hostrup mentions, occurs when acetyl, a member of the small molecule group, combines with other molecules. According to the researchers, acetylation can affect the behavior of proteins.
The study measured eight male volunteers to complete five weeks of HIIT cycling. The volunteers exercised three times per week, cycling for four minutes at a target heart rate of more than 90% of their maximum heart rate, followed by a two-minute break. This pattern was repeated four to five times per workout.
The researchers used mass spectrometry to examine changes in the composition of 3,168 proteins in tissue samples collected from the volunteers’ thighs before and after the training.
Their findings revealed an increase in the production of proteins used to construct mitochondria, which produce energy in cells, as well as proteins associated with muscle contractions. The researchers also discovered increased acetylation of mitochondrial proteins and enzymes involved in cellular energy. There were also changes in the amount of proteins that reduce skeletal muscle calcium sensitivity, which is required for muscle contractions.
The findings both confirm and identify previously unknown changes in skeletal muscle proteins that occur after exercise. Reduced calcium sensitivity, for example, may explain why muscle contraction becomes more difficult after an athlete becomes fatigued. The findings also suggest that exercise-induced changes in protein regulation via acetylation may contribute to increased 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,” says 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.”
