Glucose requirements to maintain euglycemia after moderate-intensity afternoon exercise in adolescents with type 1 diabetes are increased in a biphasic manner.
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.
McMahon
Sarah K
SK
Department of Endocrinology and Diabetes, Princess Margaret Hospital for Children, P.O. Box D184, Perth, Western Australia 6840, Australia.
Ferreira
Luis D
LD
Ratnam
Nirubasini
N
Davey
Raymond J
RJ
Youngs
Leanne M
LM
Davis
Elizabeth A
EA
Fournier
Paul A
PA
Jones
Timothy W
TW
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
D001786:Blood Glucose; D006728:Hormones; D007328:Insulin; D005947:Glucose