Impact of high-intensity interval training on Mir-21 and Mir-122 expression and metabolic parameters in middle-aged men with metabolic syndrome

Background: Metabolic syndrome, a problem of the present age, is a combination of several medical issues, and miRNAs play important regulatory roles in metabolic syndrome. Many studies indicate that high-intensity interval training (HITT) may improve risk factors for metabolic syndrome. This study aimed to investigate the effect of 8 weeks of HIIT training on the changes in miR-21, miR-122, alanine aminotransferase (ALT), aspartate aminotransferase (AST), low-density lipoprotein (LDL), lipid profile, and glucose. Methods: In this quasi-experimental study, middle-aged male (n=19) volunteers with metabolic syndrome (body mass index (BMI)>30) were randomly assigned to the control (n=9) and training (n=10) groups. The training program consisted of 8 weeks of HIIT training with 4 sets of workouts with an intensity of 80-90% heart rate for the training group (3 sessions per week during the first 4 weeks and 4 sessions per week during the second 4 weeks). Blood samples were collected from the subjects 48 hours before and after the last training session to analyze miR-21, miR-122, ALT, AST, HDL, LDL, triglyceride, cholesterol, and glucose. The within-group and between-group differences of data were analyzed using the paired t-tests and analysis of covariance at a significance level of P˂0.05 in SPSS software. Results: This study indicated that HIIT caused a significant decrease in miR-122, ALT, AST, triglyceride, cholesterol, glucose, body weight indicators, fat percentage, and BMI (P˂0.05). Also, a significant increase in miR-21 and HDL levels was observed following HIIT training (P˂0.05). Conclusion: HIIT training seems essential in metabolic changes, such as reducing the lipid profile, decreasing glucose, and improving liver damage by affecting miR-21 and miR-122 indicators as small regulatory transcripts. However, more extensive studies are needed in this field.