Effect of Training and Detraining on In Vivo Insulin Sensitivity

Insulin sensitivity was determined in rats to clarify the effect of detraining at 1 (trained state), 2, 3, and 7 days (7 rats each) and 14 days (n = 8) after five weeks of voluntary training using euglycemic insulin clamp technique. The relationship between basal insulin and glucose shifted towards a decrease in metabolic insulin needs compared to untrained controls (n = 20). During the insulin clamp study, to maintain comparable plasma glucose and insulin levels in all groups, the glucose infusion rate had to be increased significantly (p less than 0.01) to 9.92 +/- 1.12 mg.kg-1.min-1 compared to control group (6.57 +/- 0.57). This improved sensitivity persisted for 2 days after training but was significantly lowered in the 7-days-after group (p less than 0.01). In summary, this study shows that training effect on insulin sensitivity can be determined after voluntary training in rat. This training effect lasted 2 days after training.