title: Aerobic exercise increases peripheral and hepatic insulin sensitivity in sedentary adolescents.
abstract: 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.
authors.affiliation: Department of Pediatrics (G.-J.v.d.H., A.L.S.), Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: Gert-Jan
authors.initials: GJ
authors.lastname: van der Heijden
authors.forename: Gianna
authors.initials: G
authors.lastname: Toffolo
authors.forename: Erica
authors.initials: E
authors.lastname: Manesso
authors.forename: Pieter J J
authors.initials: PJ
authors.lastname: Sauer
authors.forename: Agneta L
authors.initials: AL
authors.lastname: Sunehag
mesh_terms: 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
chemical_list: D001786:Blood Glucose; D007328:Insulin; D017666:Deuterium Oxide; D005990:Glycerol