(DCP036) EFFECT OF TWO PERCENTAGES OF INSULIN BASAL RATE REDUCTION FOR TWO TYPES OF EXERCISE IN ADULTS AND ADOLESCENTS LIVING WITH TYPE 1 DIABETES

Background: Regular exercise is associated with physical and mental health benefits. However, maintaining adequate glucose control around exercise is challenging and the risk of exercise-related hypoglycemia frequently leads people living with type 1 diabetes (PWT1D) to remain sedentary. Strategies such as insulin basal rate reduction (BRR) can limit this risk in PWT1D using continuous subcutaneous insulin infusion (CSII). However, the impact of physical activity on glycemia varies depending on the type of exercise and the optimal BRR to limit the risk of hypoglycemia during different types of exercises has not been evaluated. We aim to assess the optimal BRR to minimize the risk of hypoglycemia during two types of exercise (High intensity intermittent exercise (INT) and continuous moderate intensity exercise (CONT)) known to have different impacts on glucose profiles.

METHODS AND RESULTS: Twenty-nine PWT1D treated with CSII (20 adults, 9 adolescents; HbA1c = 7.4 ± 1.0%) were included. Participants performed two 60-min exercise sessions matched for energy expenditure (CONT, 60% of VO2peak vs. INT, 2-min, 50%/2-min, 85% of VO2peak). Insulin basal rate was reduced by either 40- or 80%, 90-min before exercise start. The four interventions were carried out in a randomized fashion. Blood glucose was measured every 10-min during exercise.

Results: For CONT, there were no differences in the time spent in hypoglycemia (9.4 ± 14.0%, CONT-40%; 9.5 ± 12.0%, CONT-80%), or in the number of hypoglycemic episodes (10, CONT-40% vs. 10, CONT-80%). For INT, time spent in hypoglycemia was significantly lower with 80% BRR (9.8 ± 13.6%, INT-40%; vs. 6.4 ± 11.6%, INT-80%, p=0.04) as well as the number of hypoglycemia episodes (16, INT-40% vs. 8, INT-80%, p=0.04).

Conclusion: For CONT exercise, reducing insulin basal rate by either 40% or 80% 90 min prior to exercise had no impact on hypoglycemic risk. For INT exercise reducing basal rate by 80% should be preferred. To further reduce hypoglycemic risk, favoring exercise sessions of less than 40min and/or combining basal rate reduction with carbohydrate intake is probably required.