Exercise Detection Study
Condition: Type 1 Diabetes
MeSH terms: Diabetes Mellitus, Type 1
Study type: Interventional

Summary: 
      The risk of hypoglycemia in individuals with type 1 diabetes increases considerably during
      exercise. As a result, many patients with type 1 diabetes experience fear of and reluctance
      to pursue physical activity, in order to avoid the discomforting symptoms associated with
      hypoglycemia. The bi-hormonal artificial pancreas, a device used for automatic delivery of
      insulin and glucagon subcutaneously to subjects with type 1 diabetes, is paving the way to
      revolutionize the management of this disease. The investigator's group has recently completed
      a study of the bi-hormonal artificial pancreas system during exercise, suggesting reduced
      hypoglycemia around the exercise period. In order to prepare for a future home study, the
      ability to detect, grade, and classify physical activity so as to appropriately adjust system
      parameters is vital in helping to prevent exercise induced hypoglycemia in the home setting.

      This study is designed to collect 3-axis accelerometry data and heart rate data during a
      variety of different home activities, as well as during formal exercise in both healthy
      subjects and subjects with type 1 diabetes. Additionally, the investigators will observe the
      change in glucose levels before and after exercise in subjects with type 1 diabetes.
    

Detailed description: 
      The artificial pancreas, a device used for automatic delivery of insulin and glucagon
      subcutaneously to subjects with type 1 diabetes, is paving the way to revolutionize the
      management of this disease. Already, the benefit of improved glycemic control compared to
      current open-loop pump therapy has been demonstrated in several trials. The investigator's
      group has shown that artificial pancreas algorithm dual hormone system effectively manages
      blood glucose in a clinic setting and the investigators have specifically shown great
      progress using glucagon to reduce hypoglycemic episodes outside of exercise. The
      investigators most recent inpatient study, as yet unpublished, shows that adjusting insulin
      and glucagon delivery during closed loop treatment, after announcing exercise, effectively
      reduces mean time below a glucose level of 70 mg/dl when compared to closed loop control
      without adjustments. The investigators utilized initial open-loop data from this study to
      help devise dosing changes for the artificial pancreas algorithm.

      In order to prepare for a future home study, the ability to detect, grade, and classify
      physical activity so as to appropriately adjust system parameters is vital in helping to
      prevent exercise induced hypoglycemia in the home setting. Currently, our closed-loop system
      transmits heart rate and accelerometry outputs from a Zephyrlife BioPatch monitoring device
      to a Nexus 5 smart phone master controller via Bluetooth. The algorithm then converts the
      heart rate and accelerometry data into modified estimated energy expenditure - accounting for
      age, weight, height, sex, resting and sitting heart rates - to determine if exercise is
      present. However, further data collection is needed to hone the specificity and sensitivity
      of the detection algorithm to account for a wide variety of subject characteristics and
      activities.

      This study is designed to collect 3-axis accelerometry data and heart rate data during a
      variety of different home activities, as well as during formal exercise, which included
      aerobic exercise (on a calibrated treadmill) and resistance exercise (straight-leg raises or
      equivalent) in healthy subjects as well as subjects with type 1 diabetes. Optionally VO2 data
      from a portable VO2 mask will be obtained. The data collected will be used to further enhance
      our algorithm that, in future closed-loop studies, will detect exercise and automatically
      trigger algorithmic adjustments to reduce exercise-related hypoglycemia during and after
      exercise in individuals with type 1 diabetes.
    

Intervention name(s): Aerobic Exercise; Resistance Exercise
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Exercise for three 15 minute periods, with 10 minute rests between each period, and exercise intensity will vary between periods to achieve different energy expenditures, which may be determined based on VO2 measurements.; Subjects will perform 5-15 minutes of up to 7 different activities of daily living, followed by 20 minutes of resistance exercise, such as straight leg raises.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: exercise; artificial pancreas; hypoglycemia; type 1 diabetes