Effects of antecedent prolonged exercise on subsequent counterregulatory responses to hypoglycemia

30 healthy subjects (15 females, 15 males), age 27 +/- 1 yr, BMI 22 +/- 1 kg/m2, HbA1c 5.6 +/- 0.5%

90-min morning and afternoon cycle exercise at 50% maximal O2 uptake (VO2max) on Day 1

Equivalent rest periods on Day 1

Counterregulatory responses to subsequent hypoglycemia (norepinephrine, epinephrine, glucagon, growth hormone, pancreatic polypeptide, muscle sympathetic nerve activity, and endogenous glucose production) during a 2-h hypoglycemic clamp on Day 2surrogate