title: Effects of moderate-to-vigorous intensity physical activity on overnight and next-day hypoglycemia in active adolescents with type 1 diabetes.
abstract: OBJECTIVE
  Physical activity (PA) provides many benefits to adolescents with type 1 diabetes; however, these individuals tend to have lower fitness and PA levels than their disease-free counterparts. The purpose of this study was to examine the acute temporal associations between moderate-to-vigorous intensity PA (MVPA) and hypoglycemia (continuous glucose monitor [CGM] reading ≤70 mg/dL).
  
  
  METHODS
  Nineteen participants (53% females) 14-20 years old with type 1 diabetes were recruited. Participant fitness was evaluated via indirect calorimetry using a maximal exercise test; body composition was measured using air displacement plethysmography. An accelerometer was worn continuously (3-5 days) and acceleration data used to estimate MVPA (minutes per day). Blood glucose values were simultaneously tracked using CGM. Controlling for sex, percent body fat (%BF), fitness, and concurrent MVPA, the likelihood of nighttime and next-day hypoglycemia due to MVPA was examined using logistic regression.
  
  
  RESULTS
  Participants were of average fitness (females: 43.9 mL/kg/min; males: 49.8 mL/kg/min) and adiposity (females: 26.2%; males: 19.2%); 63.2% met the U.S. federal guideline of accumulating 60 min/day of MVPA. Hypoglycemia was 31% more likely in those who accumulated 30 min/day more MVPA in the previous afternoon than those with less (95% CI 1.05-1.63; P = 0.017).
  
  
  CONCLUSIONS
  The results suggest that participating in afternoon MVPA increases the risk of overnight and next-day hypoglycemia, independent of sex, %BF, fitness, and concurrent MVPA. While promoting PA as a healthy behavior, it is important to educate adolescents with type 1 diabetes on prevention of hypoglycemia following PA.
authors.affiliation: Corresponding author: Kristen M. Metcalf, kristen-metcalf@uiowa.edu.
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Metcalf
authors.forename: Ajay
authors.initials: A
authors.lastname: Singhvi
authors.forename: Eva
authors.initials: E
authors.lastname: Tsalikian
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Tansey
authors.forename: M Bridget
authors.initials: MB
authors.lastname: Zimmerman
authors.forename: Dale W
authors.initials: DW
authors.lastname: Esliger
authors.forename: Kathleen F
authors.initials: KF
authors.lastname: Janz
mesh_terms: D000273:Adipose Tissue / Q000502:physiology; D050154:Adiposity / Q000502:physiology; D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000502:physiology; D002153:Calorimetry, Indirect; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D015438:Health Behavior; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology* / Q000517:prevention & control; D008297:Male; D012737:Sex Factors
chemical_list: D001786:Blood Glucose