Aerobic exercise increases peripheral and hepatic insulin sensitivity in sedentary adolescents.
BACKGROUND
Data are limited on the effects of controlled aerobic exercise programs (without weight loss) on insulin sensitivity and glucose metabolism in children and adolescents.


OBJECTIVE
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.


METHODS
Twenty-nine post-pubertal adolescents (14 lean: 15.1 +/- 0.3 y; 20.6 +/- 0.8 kg/m(2); 18.9+/-1.5% body fat and 15 obese: 15.6 +/- 0.4 y; 33.2 +/- 0.9 kg/m(2); 38.4 +/- 1.4% body fat) (mean +/- SE), completed a 12 wk aerobic exercise program (4 x 30 min/week at >or=70% of VO(2) peak). Peripheral and hepatic insulin sensitivity and glucose kinetics were quantified using GCMS pre- and post-exercise.


RESULTS
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).


CONCLUSIONS
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.
van der Heijden
Gert-Jan
GJ
Department of Pediatrics (G.-J.v.d.H., A.L.S.), Baylor College of Medicine, Houston, Texas 77030, USA.
Toffolo
Gianna
G
Manesso
Erica
E
Sauer
Pieter J J
PJ
Sunehag
Agneta L
AL
D000293:Adolescent; D000332:Aerobiosis / Q000502:physiology*; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D015992:Body Mass Index; D001835:Body Weight; D017666:Deuterium Oxide; D015444:Exercise / Q000502:physiology*; D005990:Glycerol / Q000097:blood; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008019:Life Style; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D009765:Obesity / Q000503:physiopathology*; D010349:Patient Compliance; D010809:Physical Fitness / Q000502:physiology*; D013851:Thinness / Q000503:physiopathology
D001786:Blood Glucose; D007328:Insulin; D017666:Deuterium Oxide; D005990:Glycerol