Grant: Project Grant

In type 1 diabetes (T1D), secretion of insulin, a vital hormone to reduce blood sugar, is lost. Thus, patients with T1D need life-long intensive insulin therapy using multiple daily injections or insulin pump therapy. Because patients with T1D lose normal reduction of insulin during exercise, their blood glucose levels may fall rapidly thus increasing the risk of hypoglycemia (low blood sugar with malaise and risk of convulsion & coma). This risk is not only increased during exercise but also for up to 24 hours following exercise when the body reconstitutes its stores of sugar. We have shown that fear of hypoglycemia is a major limitation for physical activity for patients with T1D. Various strategies have been proposed to reduce the risk of exercise-induced hypoglycemia such as reduction in insulin dose in the hours preceding the exercise and food intake containing sugar but none fully reduces the risk of hypoglycemia. Insulin pump therapy allows more flexible treatment than multiple injections since it allows suspending or reducing insulin infusion before, during and after exercise. However, very few studies have investigated how patients should implement this strategy. Therefore, to reduce the risk of exercise-induced hypoglycemia, the objective of this application will be to determine in 3 complementary trials 1) the best timing to initiate a reduction in insulin infusion (how long before exercise?); 2) the optimum insulin infusion reduction (how much during exercise?) and 3) the best strategy to control post-exercise glucose levels (prolonged insulin reduction or snack?). We believe that the results of these trials will identify new strategies to prevent hypoglycemia and thus encourage patients with T1D to practice regular physical activity. Increased physical activity should improve quality of life and could reduce the risk of obesity and cardiovascular disease.