Prevention of exercise-associated dysglycemia: a case study-based approach.

Abstract

Regular physical activity is associated with many health benefits for people with type 1 diabetes, including improved quality of life, increased vigor, enhanced insulin sensitivity, and protection against cardiovascular disease and other diabetes-related complications (1). Despite its benefits, exercise can aggravate dysglycemia because it causes major changes to glucose production and utilization rates (2). For example, mild to intense aerobic exercise (e.g., walking, cycling, jogging, and most individual and team sports) increases the risk of hypoglycemia during the activity and in recovery because of impaired rates of glucose production, whereas very intense aerobic exercise (>80% of maximal aerobic capacity) and anaerobic exercise (e.g., sprinting and heavy weightlifting) can cause glucose levels to rise because of reduced rates of glucose disposal (3,4). Numerous strategies have been developed to help limit hypoglycemia during exercise in individuals with type 1 diabetes. One of the main reasons hypoglycemia occurs is the inability to naturally reduce insulin levels at the onset of exercise (1). Strategies to help limit hypoglycemia include exercising in the fasted state (5), reducing the insulin for the meal before exercise (6,7), interrupting basal insulin infusion for patients on insulin pump therapy (8–10), and increasing carbohydrate intake (11–14). Continuous glucose monitoring (CGM) can also help to prevent hypoglycemia in people with type 1 diabetes (15). In contrast, very little has been done to develop strategies for exercise-associated hyperglycemia, even though the mechanisms for this effect are largely established (16). The inability to naturally raise insulin levels after intense exercise to combat a rise in catecholamines is the main reason why post-exercise hyperglycemia occurs (17), although excursions associated with aggressive insulin reductions or excessive carbohydrate intake also likely bear some blame (18). In instances of exercise-associated hyperglycemia caused by intense exercise, insulin concentrations …