Prolonged Exercise in Type 1 Diabetes: Performance of a Customizable Algorithm to Estimate the Carbohydrate Supplements to Minimize Glycemic Imbalances

Abstract

Physical activity in patients with type 1 diabetes (T1DM) is hindered because of the high risk of glycemic imbalances. A recently proposed algorithm (named Ecres) estimates well enough the supplemental carbohydrates for exercises lasting one hour, but its performance for prolonged exercise requires validation. Nine T1DM patients (5M/4F; 35–65 years; HbA1c 54±13 mmol·mol-1) performed, under free-life conditions, a 3-h walk at 30% heart rate reserve while insulin concentrations, whole-body carbohydrate oxidation rates (determined by indirect calorimetry) and supplemental carbohydrates (93% sucrose), together with glycemia, were measured every 30 min. Data were subsequently compared with the corresponding values estimated by the algorithm. No significant difference was found between the estimated insulin concentrations and the laboratory-measured values (p = NS). Carbohydrates oxidation rate decreased significantly with time (from 0.84±0.31 to 0.53±0.24 g·min-1, respectively; p<0.001), being estimated well enough by the algorithm (p = NS). Estimated carbohydrates requirements were practically equal to the corresponding measured values (p = NS), the difference between the two quantities amounting to –1.0±6.1 g, independent of the elapsed exercise time (time effect, p = NS). Results confirm that Ecres provides a satisfactory estimate of the carbohydrates required to avoid glycemic imbalances during moderate intensity aerobic physical activity, opening the prospect of an intriguing method that could liberate patients from the fear of exercise-induced hypoglycemia.

Physical Activity and Diabetes

“…These strategies can be used alone or in combination (81,82). Increasing carbohydrate intake just before, during and immediately after exercise is a simple and effective way to prevent hypoglycemia, although the optimal carbohydrate intake rate varies based on the duration and intensity of the activity and the amount of insulin in the circulation at the time of exercise (78,83,84). For activities less than 2 hours after a meal, reductions in prandial insulin by 25% to 75% are effective in limiting hypoglycemia (77).…”

Mini-Dose Glucagon as a Novel Approach to Prevent Exercise-Induced Hypoglycemia in Type 1 Diabetes

“…However, exercise-associated hypoglycemia and the complexity of management aimed at its prevention represent major barriers to the adoption of regular physical activity for many individuals with type 1 diabetes (3)(4)(5)(6)(7). Although carbohydrate ingestion can help ameliorate hypoglycemia in patients with type 1 diabetes, patients' carbohydrate requirements can be as high a 1 g/min of exercise (8), which can be counterproductive from a weight management perspective.…”

Glycemic Index of Pre-Exercise Meal in Diabetes Mellitus: A Systematic Review

“…24,25 In contrast, in recent studies of exercise and DM type 1, pre-exercise food GI is not clearly considered as a nutritional care option for glycemic control during physical exercise. 26,27 This current view may reflect that the relevance of GI to clinical practice is not yet clear.…”