The persistence of changes in insulin sensitivity and metabolic gene expression after acute exercise in male and female mice.

Background: Acute exercise has been suggested to increase insulin sensitivity, although the duration of the improvement may last anywhere from 4 to 72 h. In addition, changes in gene expression in response to exercise is suggested to last at least 24 h. Despite this, exercise training studies assess metabolism anywhere from immediately after to 72 h after the last exercise session, which could confuse the acute versus chronic exercise effects. Therefore, the purpose of this study was to assess the duration of changes in insulin sensitivity after acute exercise and the impact of acute exercise on metabolic gene expression. Materials and methods: Male and female mice endured a single bout of aerobic exercise and underwent insulin sensitivity tests at 30 min, 4 h, and 24 h following acute exercise. Furthermore, skeletal muscle was harvested, and gene expression analysis was performed at 30 min and 24, 48, and 72 h after the exercise bout. Results: Females had increased insulin sensitivity compared to males independent of exercise. However, males showed increased sensitivity 30 min following exercise while females did not. Neither males nor females had improved insulin sensitivity 24 h following exercise. Both male and female mice had upregulation of several metabolic genes 24 h after acute exercise, which was comparable to sedentary controls after 48-72 h of recovery. Conclusions: The results show that acute exercise does not significantly affect insulin sensitivity 24 h after exercise but the effects of acute exercise on metabolic gene expression persist after 24 h and return to baseline within 48-72 h.