title: The effects of aerobic exercise on glucose and counterregulatory hormone concentrations in children with type 1 diabetes.
abstract: OBJECTIVE
  To examine the acute glucose-lowering effects of aerobic exercise in children and adolescents with type 1 diabetes.
  
  
  METHODS
  Fifty children and adolescents with type 1 diabetes (ages 10 to <18 years) were studied during exercise. The 75-min exercise session consisted of four 15-min periods of walking on a treadmill to a target heart rate of 140 bpm and three 5-min rest periods. Blood glucose and plasma glucagon, cortisol, growth hormone, and norepinephrine concentrations were measured before, during, and after exercise.
  
  
  RESULTS
  In most subjects (83%), plasma glucose concentration dropped at least 25% from baseline, and 15 (30%) subjects became hypoglycemic (< or = 60 mg/dl) or were treated for low glucose either during or immediately following the exercise session. The incidence of hypoglycemia and/or treatment for low glucose varied significantly by baseline glucose, occurring in 86 vs. 13 vs. 6% of subjects with baseline values <120, 120-180, and >180 mg/dl, respectively (P < 0.001). Exercise-induced increases in growth hormone and norepinephrine concentrations were marginally higher in subjects whose glucose dropped < or = 70 mg/dl. Treatment of hypoglycemia with 15 g of oral glucose resulted in only about a 20-mg/dl rise in glucose concentrations.
  
  
  CONCLUSIONS
  In youth with type 1 diabetes, prolonged moderate aerobic exercise results in a consistent reduction in plasma glucose and the frequent occurrence of hypoglycemia when preexercise glucose concentrations are <120 mg/dl. Moreover, treatment with 15 g of oral glucose is often insufficient to reliably treat hypoglycemia during exercise in these youngsters.
authors.affiliation: DirecNet Coordinating Center, Jaeb Center for Health Research, Tampa, FL 33647, USA. direcnet@jaeb.org
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Tansey
authors.forename: Eva
authors.initials: E
authors.lastname: Tsalikian
authors.forename: Roy W
authors.initials: RW
authors.lastname: Beck
authors.forename: Nelly
authors.initials: N
authors.lastname: Mauras
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Buckingham
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Weinzimer
authors.forename: Kathleen F
authors.initials: KF
authors.lastname: Janz
authors.forename: Craig
authors.initials: C
authors.lastname: Kollman
authors.forename: Dongyuan
authors.initials: D
authors.lastname: Xing
authors.forename: Katrina J
authors.initials: KJ
authors.lastname: Ruedy
authors.forename: Michael W
authors.initials: MW
authors.lastname: Steffes
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Borland
authors.forename: Ravinder J
authors.initials: RJ
authors.lastname: Singh
authors.forename: William V
authors.initials: WV
authors.lastname: Tamborlane
mesh_terms: D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D005080:Exercise Test; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D007003:Hypoglycemia / Q000453:epidemiology; D009638:Norepinephrine / Q000097:blood*; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D019382:Human Growth Hormone; D009638:Norepinephrine