Aim 2 is to evaluate the incremental utility of glucagon in the context of automated insulin delivery by the bionic pancreas in preventing hypoglycemia during exercise in the fasted state. The 130 mg/dl set points and 110 mg/dl set points also participate in this fasted exercise visit. These two set points are double blinded, so neither the subjects nor the study staff are aware which arm is bihormonal and which arm is insulin only.