EXERCISE-INDUCED HYPOGLYCEMIA IN IDDM PATIENTS TREATED WITH A SHORT-ACTING INSULIN ANALOG

In order to examine the effect of short-acting insulin analogue on the exercise-induced hypoglycaemia in insulin-dependent diabetes mellitus (IDDM) patients we compared the glycaemic response of 40 min cycle ergometer exercise performed either shortly (40 min) or later (180 min) after a breakfast meal and subcutaneous injection of either short-acting insulin analogue [Lys(B28) Pro(B29)] or soluble human insulin (Humulin Regular) in ten IDDM patients with long duration of the disease. Both preparations had been used 1 month before respective studies. Changes in blood glucose, insulin and counterregulatory hormones were assayed. As compared to human insulin, after the analogue injection the peak insulin concentration came earlier, was 56% higher (p < 0.05) and disappeared faster, and the postprandial blood glucose response was lower (p < 0.05). In the analogue-treated patients the exercise-induced hypoglycaemia was 2.2-fold greater (p < 0.01) during the early exercise, but 46% less (p < 0.05) during late exercise as compared to the treatment with human insulin. Serum insulin or analogue concentration at the beginning of the exercise correlated closely with the fall in blood glucose during exercise (r = 0.74, p < 0.01; r = 0.73, p < 0.02, respectively). In the analogue-treated patients, fasting serum glucagon and adrenalin concentrations were higher than during human insulin therapy (p < 0.05) and remained so throughout the study. As compared to soluble human insulin, a much faster absorption of insulin analogue: 1) reduces post-prandial hyperglycaemia, 2) can either augment or reduce exercise-induced hypoglycaemia depending on the time interval between insulin injection and the time of exercise. Since exercise is usually not performed until 2-3 h after a meal, short-acting insulin analogue may be more feasible than soluble human insulin for active IDDM patients.