The impact of six weeks of continuous training and high-intensity intermittent training on pancreatic functions of Streptozocin-induced diabetic rats

Type 2 diabetes is a health problem involving insulin resistance and beta cell dysfunction. Physical activity can enhance insulin sensitivity and protect beta cell function. The present study investigates the effect of 6 weeks of continuous training and high-intensity interval training on serum Growth Differentiation Factor 11 (GDF11) levels and pancreatic functions of STZ-induced diabetic rats.

Forty male Wistar rats (200-250 g) were fed a high-fat diet for 4 weeks and given intraperitoneal 30 mg/kg STZ injections. They were divided into four groups, each with 10 rats: non-diabetes, diabetes, diabetic + high-intensity intermittent training (HIIT), and diabetes + continuous training (CT). CT exercised at 15 m/min while HIIT was trained at 26 m/min, both 6 days a week over 6 weeks. Measurements included body weight, food and water intake, fasting blood glucose and insulin, GDF11, hemoglobin A1c, and pancreatic function indices.

In diabetic rats, body weight, beta cell function, and insulin sensitivity decreased, while water and food intake, as well as glucose, insulin, HbA1c levels, and insulin resistance, increased compared to non-diabetic rats. Both HIIT and CT interventions reduced water and food intake, along with glucose, insulin, and HbA1c levels in diabetic rats. There were no significant differences in GDF11 levels between diabetic and exercise groups.

Our results suggest that HIIT and CT may reduce metabolic disturbances in diabetes, but their effects are limited. Furthermore, these training models affect neither GDF11 nor training adaptations in diabetic rats mediated by GDF11.