title: Glucose requirements to maintain euglycemia after moderate-intensity afternoon exercise in adolescents with type 1 diabetes are increased in a biphasic manner.
abstract: BACKGROUND
  Exercise increases the risk of hypoglycemia in type 1 diabetes.
  
  
  OBJECTIVE
  This study aimed to investigate how the amount of glucose required to prevent an exercise-mediated fall in glucose level changes over time in adolescents with type 1 diabetes.
  
  
  METHODS
  The study took place at a tertiary pediatric referral center.
  
  
  METHODS
  Nine adolescents with type 1 diabetes mellitus (five males, four females, aged 16 +/- 1.8 yr, diabetes duration 8.2 +/- 4.1 yr, hemoglobin A1c 7.8 +/- 0.8%, mean +/- SD) were subjected on two different occasions to a rest or 45 min of exercise at 95% of their lactate threshold. Insulin was administered iv at a rate based on their usual insulin dose, with similar plasma insulin levels for both studies (82.1 +/- 19.0, exercise vs. 82.7 +/- 16.4 pmol/liter, rest). Glucose was infused to maintain euglycemia for 18 h.
  
  
  METHODS
  Glucose infusion rates required to maintain euglcycemia and levels of counterregulatory hormones were compared between rest and exercise study nights.
  
  
  RESULTS
  Glucose infusion rates to maintain stable glucose levels were elevated during and shortly after exercise, compared with the rest study, and again from 7-11 h after exercise. Counterregulatory hormone levels were similar between exercise and rest studies except for peaks in the immediate postexercise period (epinephrine, norepinephrine, GH, and cortisol peaks: 375.6 +/- 146.9 pmol/liter, 5.59 +/- 0.73 nmol/liter, 71.9 +/- 14.8 mIU/liter, and 558 +/- 69 nmol/liter, respectively).
  
  
  CONCLUSIONS
  The biphasic increase in glucose requirements to maintain euglycemia after exercise suggests a unique pattern of early and delayed risk for nocturnal hypoglycemia after afternoon exercise.
authors.affiliation: Department of Endocrinology and Diabetes, Princess Margaret Hospital for Children, P.O. Box D184, Perth, Western Australia 6840, Australia.
authors.forename: Sarah K
authors.initials: SK
authors.lastname: McMahon
authors.forename: Luis D
authors.initials: LD
authors.lastname: Ferreira
authors.forename: Nirubasini
authors.initials: N
authors.lastname: Ratnam
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Davey
authors.forename: Leanne M
authors.initials: LM
authors.lastname: Youngs
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Davis
authors.forename: Paul A
authors.initials: PA
authors.lastname: Fournier
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D001786:Blood Glucose / Q000032:analysis*; D002940:Circadian Rhythm; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects; D015444:Exercise / Q000502:physiology*; D005260:Female; D005947:Glucose / Q000008:administration & dosage*; D006728:Hormones / Q000097:blood; D006801:Humans; D007003:Hypoglycemia / Q000517:prevention & control*; D007260:Infusion Pumps; D007328:Insulin / Q000097:blood; D008297:Male
chemical_list: D001786:Blood Glucose; D006728:Hormones; D007328:Insulin; D005947:Glucose