Effects of High-Intensity Intermittent Training on Metabolic Parameters and Irisin Levels in High-Fat-Fed Rats

Objective: To investigate the effects of high-intensity intermittent training (HIIT) on preventing significant weight gain and provide scientific theoretical support and practical guidance for reducing the occurrence of obesity. Methods: Twenty-four Sprague-Dawley rats were randomly divided into four groups: the control sedentary group (CS), the high-fat sedentary group (HS), the high-fat continuous exercise group (HE), and the high-fat intermittent exercise group (HI). The HE and HI groups underwent five days of continuous low-intensity exercise and eight weeks of high-intensity intermittent exercise. Weekly monitoring included measurements of food intake and body weight. An automatic biochemical analyzer was used to assess blood lipid and glucose levels, while ELISA kits measured serum insulin and irisin content. H&E staining was used to observe adipocyte size. Results: In the HS group, body weight, blood lipid levels, blood glucose levels, and adipocyte size significantly increased, while the QUICKI index decreased. In the HI group, body weight, blood lipid levels, blood glucose levels, and adipocyte size decreased, and the QUICKI index increased. The effects of high-intensity intermittent exercise were superior to those of continuous low-intensity exercise. In the HI group, serum irisin levels did not change significantly after exercise, while in the HE group, there was a slight upward trend in irisin levels. Conclusion: A high-fat diet induced abnormal metabolism in rats. HIIT effectively prevents metabolic abnormalities induced by a high-fat diet, and its effects are more pronounced than those of low-intensity exercise. HIIT stimulates the secretion of blood irisin, affecting secretion levels, and may represent a novel mechanism for maintaining metabolic homeostasis. This has important implications for controlling significant weight gain.