Guidelines for premeal insulin dose reduction for postprandial exercise ofdifferent intensities and durations in type 1 diabetic subjects treated intensively with a basal-bolus insulin regimen (Ultralente-Lispro)

OBJECTIVE - To evaluate and validate appropriate premeal insulin dose reduc tions for postprandial exercises of different intensities and durations to minimize the risk of exercise-induced hypoglycemia in type 1 diabetic subje cts. RESEARCH DESIGN AND METHODS - Eight male type 1 diabetic patients on a basa l-bolus insulin regimen of ultralente (UL) as basal insulin and lispro (LP) as premeal insulin were tested in a randomized, crossover fashion during p ostprandial exercise at 25% VO2max lot 60 min. 50% VO2max for 30 and 60 min , and 75% VO2max for 30 min starting 90 min alter a standardized mixed brea kfast (600 kcal, 75 g carbohydrates). Each subject served as his own contro l and was tested after a full dose of insulin LP (LP 100%) and/or 50% (LP 5 0%) and/or 25% (LP 25%) of the current dose. RESULTS - At all intensities. the full premeal insulin dose was associated with an increased risk of hypoglycemia. At 25% VO2max for 60 min, a 50% red uction in the premeal insulin dose resulted in plasma glucose of -0.62 mmol /l compared with baseline at the end of exercise. At 50% VO2max for 30 and 60 min. 50 and 75% reductions of thr premeal insulin dose were associated w ith plasma glucose of -0.39 and +0.49 mmol/l, respectively, at the end of t he exercise. At 75% VO2max, a 75% reduction of the premeal insulin dose was required to achieve appropriate postexercise plasma glucose (+0.71 mmol/l) . Such reductions in the premeal insulin dose resulted in a 75% decrease in the incidence of exercise-induced hypoglycemia. CONCLUSIONS - In well-controlled type 1 diabetic subjects on intensive insu lin therapy with the basal-bolus (UL-LP) insulin regimen, risk of hypoglyce mia can be minimized during postprandial exercises of different different i ntensities and different durations by appropriate reduction of premeal insu lin LP.