title: Heart rate informed artificial pancreas system enhances glycemic control during exercise in adolescents with T1D.
abstract: OBJECTIVE
  To evaluate the safety and performance of using a heart rate (HR) monitor to inform an artificial pancreas (AP) system during exercise among adolescents with type 1 diabetes (T1D).
  
  
  METHODS
  In a randomized, cross-over trial, adolescents with T1D age 13 - 18 years were enrolled to receive on separate days either the unmodified UVa AP (stdAP) or an AP system connected to a portable HR monitor (AP-HR) that triggered an exercise algorithm for blood glucose (BG) control. During admissions participants underwent a structured exercise regimen. Hypoglycemic events and CGM tracings were compared between the two admissions, during exercise and for the full 24-hour period.
  
  
  RESULTS
  Eighteen participants completed the trial. While number of hypoglycemic events during exercise and rest was not different between visits (0.39 AP-HR vs 0.50 stdAP), time below 70 mg dL-1was lower on AP-HR compared to stdAP, 0.5±2.1% vs 7.4±12.5% (P = 0.028). Time with BG within 70-180 mg dL-1was higher for the AP-HR admission vs stdAP during the exercise portion and overall (96% vs 87%, and 77% vs 74%), but these did not reach statistical significance (P = 0.075 and P = 0.366).
  
  
  CONCLUSIONS
  Heart rate signals can safely and efficaciously be integrated in a wireless AP system to inform of physical activity. While exercise contributes to hypoglycemia among adolescents, even when using an AP system, informing the system of exercise via a HR monitor improved time <70 mg dL-1. Nonetheless, it did not significantly reduce the total number of hypoglycemic events, which were low in both groups.
authors.affiliation: Center for Diabetes Technology, University of Virginia, Charlottesville, Virginia.|Division of Pediatric Endocrinology, Department of Pediatrics, University of Virginia, Charlottesville, Virginia.
authors.forename: Mark D
authors.initials: MD
authors.lastname: DeBoer
authors.affiliation: Center for Diabetes Technology, University of Virginia, Charlottesville, Virginia.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Cherñavvsky
authors.affiliation: Division of Endocrinology, Department of Medicine, University of Virginia, Charlottesville, Virginia.
authors.forename: Katarina
authors.initials: K
authors.lastname: Topchyan
authors.affiliation: Center for Diabetes Technology, University of Virginia, Charlottesville, Virginia.
authors.forename: Boris P
authors.initials: BP
authors.lastname: Kovatchev
authors.affiliation: Division of Endocrinology, Department of Medicine, University of Virginia, Charlottesville, Virginia.
authors.forename: Gary L
authors.initials: GL
authors.lastname: Francis
authors.affiliation: Center for Diabetes Technology, University of Virginia, Charlottesville, Virginia.|Division of Pediatric Endocrinology, Department of Pediatrics, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Marc D
authors.initials: MD
authors.lastname: Breton
mesh_terms: D000293:Adolescent; D000465:Algorithms; D001786:Blood Glucose / Q000032:analysis; D003131:Combined Modality Therapy; D018592:Cross-Over Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology / Q000628:therapy*; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006339:Heart Rate; D006801:Humans; D006943:Hyperglycemia / Q000517:prevention & control*; D007003:Hypoglycemia / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D018670:Monitoring, Ambulatory / Q000009:adverse effects; D019397:Pancreas, Artificial / Q000009:adverse effects; D012306:Risk; D012720:Severity of Illness Index; D014768:Virginia / Q000453:epidemiology; D059015:Wireless Technology
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: artificial pancreas; exercise; heart rate; monitor; type 1 diabetes