Aerobic fitness and glycemic variability in adolescents with type 1 diabetes.
OBJECTIVE
This study examines the association of fitness on glycemic variability (GV) in adolescents with type 1 diabetes mellitus (T1DM). GV has been associated with high frequency of hyper- and hypoglycemia.


METHODS
Nineteen adolescents with T1DM, ages 14 to 19 years, underwent aerobic fitness testing to determine their maximal aerobic capacity (VO2 max). A continuous glucose monitoring (CGM) device was placed on each subject and worn for 3 to 5 days until a return visit when the subjects underwent a 1-hour treadmill exercise session. Mean amplitude of glycemic excursion (MAGE) was calculated from the CGM data collected between the 2 study visits. Metabolic equivalent (MET), a measure of accumulated metabolic workload during the exercise session, was also calculated.


RESULTS
Mean VO2 max was 46.6 ± 6.8 mL/kg/min, with a range of 34.8 to 57.0 mL/kg/min. Mean MET during the exercise session was 577.2 ± 102.4 and ranged from 354.3 to 716.2 METs. There was an inverse association between VO2 max and MAGE (r = -0.46; 95% confidence interval [CI], -0.01 to -0.76; P = .048). MET load and MAGE also had an inverse relationship (r = -0.48; 95% CI, -0.03 to -0.77; P = .037).


CONCLUSIONS
GV is inversely associated with fitness and MET load. Aerobic fitness should be promoted in adolescents with T1DM not only because of its multiple beneficial effects but also due to a possible association with GV, leading to fewer extremes in hypo- and hyperglycemia.
Department of Pediatric Endocrinology and Diabetes, University of Iowa Hospital and Clinics.
Ajay
A
Singhvi
Department of Pediatric Endocrinology and Diabetes, University of Iowa Hospital and Clinics.
Michael Jeremiah
MJ
Tansey
Health and Human Physiology, University of Iowa.
Kathleen
K
Janz
College of Public Health, University of Iowa, Iowa City, Iowa.
Miriam Bridget
MB
Zimmerman
Department of Pediatric Endocrinology and Diabetes, University of Iowa Hospital and Clinics.
Eva
E
Tsalikian
D000293:Adolescent; D001786:Blood Glucose / Q000032:analysis*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D015444:Exercise; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D055815:Young Adult
D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human