title: Incorporating an Exercise Detection, Grading, and Hormone Dosing Algorithm Into the Artificial Pancreas Using Accelerometry and Heart Rate.
abstract: In this article, we present several important contributions necessary for enabling an artificial endocrine pancreas (AP) system to better respond to exercise events. First, we show how exercise can be automatically detected using body-worn accelerometer and heart rate sensors. During a 22 hour overnight inpatient study, 13 subjects with type 1 diabetes wearing a Zephyr accelerometer and heart rate monitor underwent 45 minutes of mild aerobic treadmill exercise while controlling their glucose levels using sensor-augmented pump therapy. We used the accelerometer and heart rate as inputs into a validated regression model. Using this model, we were able to detect the exercise event with a sensitivity of 97.2% and a specificity of 99.5%. Second, from this same study, we show how patients' glucose declined during the exercise event and we present results from in silico modeling that demonstrate how including an exercise model in the glucoregulatory model improves the estimation of the drop in glucose during exercise. Last, we present an exercise dosing adjustment algorithm and describe parameter tuning and performance using an in silico glucoregulatory model during an exercise event.
authors.affiliation: Department of Biomedical Engineering, Oregon Health and Science University, Portland OR, USA jacobsp@ohsu.edu.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Jacobs
authors.affiliation: Department of Biomedical Engineering, Oregon Health and Science University, Portland OR, USA.
authors.forename: Navid
authors.initials: N
authors.lastname: Resalat
authors.affiliation: Harold Schnitzer Diabetes Health Center, Oregon Health and Science University, Portland OR, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: El Youssef
authors.affiliation: Department of Biomedical Engineering, Oregon Health and Science University, Portland OR, USA.
authors.forename: Ravi
authors.initials: R
authors.lastname: Reddy
authors.affiliation: Harold Schnitzer Diabetes Health Center, Oregon Health and Science University, Portland OR, USA.
authors.forename: Deborah
authors.initials: D
authors.lastname: Branigan
authors.affiliation: Department of Biomedical Engineering, Oregon Health and Science University, Portland OR, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Preiser
authors.affiliation: Department of Biomedical Engineering, Oregon Health and Science University, Portland OR, USA.
authors.forename: John
authors.initials: J
authors.lastname: Condon
authors.affiliation: Harold Schnitzer Diabetes Health Center, Oregon Health and Science University, Portland OR, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Castle
mesh_terms: D056044:Actigraphy / Q000295:instrumentation*; D000465:Algorithms; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D003198:Computer Simulation; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D054796:Drug Dosage Calculations; D004734:Energy Metabolism; D004867:Equipment Design; D015444:Exercise; D005080:Exercise Test; D005934:Glucagon / Q000008:administration & dosage* / Q000493:pharmacokinetics; D006339:Heart Rate; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D007328:Insulin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D016014:Linear Models; D008954:Models, Biological; D019397:Pancreas, Artificial; D011237:Predictive Value of Tests; D013997:Time Factors
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D005934:Glucagon
keywords: accelerometer; energy expenditure; exercise; glucoregulatory model; heart rate; hypoglycemia