The blood glucose lowering effects of exercise and glibenclamide in patients with type 2 diabetes mellitus.

Physical exercise is associated with a fall in serum insulin levels, whereas sulphonylurea administration increases insulin release. To date, the opposing effects of exercise and sulphonylurea administration have not been systematically studied in Type 2 diabetic patients, who are not infrequently treated with sulphonylureas. In this study nine patients with Type 2 diabetes mellitus were subjected to four treatments in random order on separate days: (A) endurance exercise after the administration of 3.5 mg glibenclamide; (B) as A but given only 1.75 mg glibenclamide; (C) as A but with placebo; (D) rest and administration of 1.75 mg glibenclamide. Exercise and placebo resulted in only a small decrease in glycaemia. Rest and administration of 1.75 mg glibenclamide led to a moderate but steady fall in blood glucose concentrations. If glibenclamide administration and exercise were combined, blood glucose concentrations declined more markedly. Serum insulin concentrations showed a physiological decrease during exercise and placebo administration. If patients rested after administration of glibenclamide serum insulin levels rose and remained elevated. When exercise and glibenclamide were combined the rise in serum insulin levels was blunted and insulin levels fell once exercise was begun. Thus, exercise attenuates the glibenclamide induced increase in serum insulin in moderately hyperglycaemic Type 2 diabetic patients. Nevertheless, exercise has a substantial hypoglycaemic effect in glibenclamide treated Type 2 diabetic patients.