The effects of metformin and glibenclamide on glucose metabolism, counter-regulatory hormones and cardiovascular responses in women with Type 2 diabetes during exercise of moderate intensity.

Aims  To compare the effects of metformin and glibenclamide on cardiovascular, metabolic and hormonal parameters during exercise of moderate intensity performed in the postprandial state, in women with Type 2 diabetes. Methods  Ten patients treated with metformin, 10 with glibenclamide and 10 control subjects (C) exercised on a bicycle ergometer at 50% of oxygen uptake (VO2) peak for 45 min. Cardiovascular, blood metabolic and hormonal parameters were determined at times −60 min (fasting), 0, +15, +30, +45 min (exercise) and at +60, +90 min (recovery). Thirty minutes prior to exercise, participants consumed a standard breakfast. Patients with diabetes took metformin or glibenclamide before the meal. Results  Systolic and diastolic blood pressure and plasma glucose were higher in both diabetic groups, for the whole experiment. Blood glucose did not change during exercise in the three groups and increased at recovery only in the control group. Plasma glucagon concentrations at the end of exercise and recovery, and plasma lactate concentrations at recovery were higher in the metformin group. Insulin, noradrenaline, growth hormone, cortisol and free fatty acid responses were similar in all three groups. Conclusions  Our results suggest that the usual dose of glibenclamide and metformin can be taken safely before postprandial exercise of moderate intensity without affecting cardiovascular, metabolic and hormonal responses. However, after exercise, glibenclamide and metformin prevent the normal rise in blood glucose and metformin delays the fall in plasma lactate concentrations.