ARS | Publication request: Aerobic exercise increases peripheral and hepatic insulin sensitivity in sedentary adolescents

Submitted to: Journal of Clinical Endocrinology and Metabolism
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2009
Publication Date: October 6, 2009
Citation: Van Der Heijden, G.J., Toffolo, G., Manesso, E., Sauer, P.J.J., Sunehag, A.L. 2009. Aerobic exercise increases peripheral and hepatic insulin sensitivity in sedentary adolescents. Journal of Clinical Endocrinology and Metabolism. 94(11):4292-4299.

Interpretive Summary: Obese adolescents have reduced sensitivity to insulin placing them at increased risk of metabolic disorders for example type 2 diabetes and cardiovascular disease. A study was conducted to determine if a controlled aerobic exercise program in itself (that is without the goal of losing weight) would improve the biological response to insulin in the muscle and liver of Hispanic adolescents that live a sedentary lifestyle. Additionally, we wanted to determine whether such program would affect their production of sugar. We learned that sugar metabolism did not differ between lean and obese adolescents. In both groups, the production of sugar decreased slightly in response to the exercise program. We concluded that this well accepted aerobic exercise program, without the intent of weight loss, is a promising strategy to improve insulin sensitivity in lean and obese sedentary adolescents.

Technical Abstract: Data are limited on the effects of controlled aerobic exercise programs (without weight loss) on insulin sensitivity and glucose metabolism in children and adolescents. To determine whether a controlled aerobic exercise program (without weight loss) improves peripheral and hepatic insulin sensitivity and affects glucose production (GPR), gluconeogenesis and glycogenolysis in sedentary lean and obese Hispanic adolescents. Twenty-nine post-pubertal adolescents (14 lean: 15.1+/-0.3y; 20.6+/-0.8kg/m2; 18.9+/-1.5% body fat and 15 obese: 15.6+/- 0.4y; 33.2+/-0.9kg/m2; 38.4+/-1.4% body fat) (mean+/-SE), completed a 12 wk aerobic exercise program (4x30 min/week at greater than or equal to 70% of VO2 peak). Peripheral and hepatic insulin sensitivity and glucose kinetics were quantified using GCMS pre- and post-exercise. No weight loss occurred. Lean and obese participants complied well with the program (approximately 90% of the exercise sessions attended, resulting in approximately 15% increase in fitness in both groups). Peripheral and hepatic insulin sensitivity were higher in lean than obese adolescents but increased in both groups; peripheral insulin sensitivity by 35+/-14% (lean) (p<0.05) and 59+/-19% (obese) (p<0.01) and hepatic insulin sensitivity by 19+/-7% (lean) (p<0.05) and 23+/-4% (obese) (p<0.01). GPR, gluconeogenesis and glycogenolysis did not differ between the groups. GPR decreased slightly, 3+/-1% (lean) (p<0.05) and 4+/-1% (obese) (p<0.01). Gluconeogenesis remained unchanged, while glycogenolysis decreased slightly in the obese group (p<0.01).This well accepted aerobic exercise program, without weight loss, is a promising strategy to improve peripheral and hepatic insulin sensitivity in lean and obese sedentary adolescents. The small decrease in GPR is probably of limited clinical relevance.