Metabolic and hormonal responses to exercise in type 1 diabetic patients during continuous subcutaneous, as compared...

This study was performed to determine whether metabolic and hormonal responses during moderate exercise differ between continuous intraperitoneal insulin infusion (CIPII) and continuous subcutaneous insulin infusion (CSII). In seven Type 1 diabetic patients, treatment was changed from CSII to CIPII. Prior to the change, these patients performed an ergometer exercise at 60% of VO2max for 40 min followed by a 200-min rest. About one year later, when the procedure was repeated during CIPII, HbA1c had improved from 8.5 to 7.1%. Arterial blood glucose, venous lactate and hormonal responses were analysed. Although a regimen with a higher basal insulin infusion rate was applied during the exercise test on CIPII, corresponding venous insulin levels were lower (28.0 +/- 2.2 vs. 48.1 +/- 7.9 pmol L-1, p = 0.04). Exercise caused a more marked decline in blood glucose during CIPII, with nadir blood glucose at the end of exercise (3.6 +/- 0.4 vs. 5.1 +/- 0.4 mmol L-1, p = 0.005). Both exercise tests yielded significant and similar increases in plasma levels of adrenaline, noradrenaline, cortisol and growth hormone. A significant rise in plasma glucagon (15.1 +/- 4.5 pg mL-1, p = 0.01) was observed during CIPII, but not during CSII (7.4 +/- 3.5, pg mL-1, n.s.). It is concluded that patients on CIPII should reduce their insulin infusion rate during exercise. CIPII appears to have favourable effects on counterregulatory capacity; in particular, a more prominent glucagon response to exercise may prove important.