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

This study was performed to determine whether metabolic and hormonal respon ses during moderate exercise differ between continuous intraperitoneal insu lin infusion (CIPII) and continuous subcutaneous insulin infusion (CSII). I n 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 VO2 max for 40 min followed by a 200-min rest. About one year later, whe n the procedure was repeated during CIPII, HbA1c had improved from 8.5 to 7 .1%. Arterial blood glucose,venous lactate and hormonal responses were anal ysed. Although a regimen with a higher basal insulin infusion rate was appl ied 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 cau sed a more marked decline in blood glucose during CIPII, with nadir blood g lucose 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 plas ma levers of adrenaline, noradrenaline, cortisol and growth hormone. A sign ificant rise in plasma glucagon (15.1 +/- 4.5 pg mL(-1), p = 0.01) was obse rved during CIPII, but not during CSII (7.4 +/- 3.5, pg mL(-1), n.s.). It i s concluded that patients on CIPII should reduce their insulin infusion rat e during exercise. CIPII appears to have favourable effects on counterregul atory capacity; in particular, a more prominent glucagon response to exerci se may prove important.