Strategies used by Patients with Type 1 Diabetes to Avoid Hypoglycemia in a 24 71-Hour Marathon: Comparison with the Amounts of Carbohydrates Estimated by a Customizable Algorithm

OBJECTIVES: The preferred countermeasure to avoid exercise-related hypoglycemia was investigated in a group of patients with type 1 diabetes participating in a stressful event, a 24 71-hour relay marathon. The carbohydrates actually consumed were compared to those estimated for each patient by applying a customizable algorithm, Exercise Carbohydrates Requirement Estimating Software (ECRES), based on patient's usual therapy and diet and on the exercise characteristics. METHODS: Glycemia was tested at the start, middle and end of the races. Usual therapies and diets and the adopted countermeasures were recorded in detail. RESULTS: We studied 19 patients who walked/ran 10.4\ub12.8\u2009km with a heart rate of 167\ub111 beats per minute. Of the 19 patients, 7 patients reduced the administered insulin (premeal bolus or basal infusion rate). Glycemia fell by the end of the races (p=0.006; median -1.8\u2009mmol c5L-1; interquartile range -0.4\u2009mmol c5L-1 to -5.3\u2009mmol c5L-1), despite 9 patients being hyperglycemic at the start. Of the patients, 14 concluded the race with glycemia on target, and 4 patients were hyperglycemic. Amounts of carbohydrates actually consumed (median 30\u2009g; interquartile range 0\u2009g to 71\u2009g) were not significantly different from those estimated by ECRES (median 38\u2009g; interquartile range 24\u2009g to 68\u2009g), the 2 quantities being significantly related (R=0.64; p=0.003). ECRES estimated lower carbohydrate levels (-13\u2009g) than the amounts actually consumed by the 4 patients who concluded their exercises with hyperglycemia. CONCLUSIONS: Patients preferred to consume extra carbohydrates to avoid the possible exercise-induced hypoglycemia. ECRES would provide satisfactory estimates of the carbohydrate requirements, even for a stressful condition, and almost equal to the quantities consumed following medical advice